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User:Alandmanson/Sources of Information for smallholders in KwaZulu-Natal

This document is a guide to sources of information that may help smallholders in KwaZulu-Natal (South Africa) to produce crops and vegetables without expensive inputs.

Smallholder agriculture is practised widely in KwaZulu-Natal. Although low-cost agriculture is unlikely to raise many poor people out of poverty, it can improve household livelihoods This is because most households in the province have insufficient resources to generate a living wage from agriculture, and need other forms of income.

Smallholders in KZN generally have less than 2 ha (often less than 0.2 ha or 2000 m2) available for crop production. Despite this limitation, there are many successful smallholders; they often produce a variety of crops that may include a small patch of irrigated vegetables, a few fruit trees, and a mix of dryland (rain-fed) crops. There is a great deal of information available to help these farmers, but it is not always accessible. This document is an attempt to show what locally relevant information is available, and where it can be found (mostly on the world-wide web).

Natural resources
The availability of natural resources will limit the choice of crops that can be produced at low cost - Rainfall, temperature regime, soil type and terrain all vary considerably from place to place in KZN. At the scale of the smallholder, the soil and terrain usually require an on-site inspection to determine soil depth, soil drainage and slopes of individual fields. However, there are a number of mapping projects that can serve as guides regarding climate, soil patterns, terrain, and water availability for irrigation at the village or ward scale.

Bioresource Groups Camp, K.G.T., 1999. A bioresource classification for KwaZulu-Natal, South Africa. https://researchspace.ukzn.ac.za/handle/10413/5406

Handbook on adaptation to climate change for farmers, officials and others in the agricultural sector of South Africa https://www.daff.gov.za/daffweb3/Branches/Forestry-Natural-Resources-Management/Climate-Change-and-Disaster-Management/Climate-Change-Unit

Agrohydrology Atlas

DWAS regulations regarding use of surface water

Climate-smart Agriculture
There are many low-cost technologies available that can help smallholders make the most of the limited climatic resources available to them.

Conservation Agriculture
No-Till Crop Production For KwaZulu-Natal https://archive.org/details/no-till-crop-production-for-kzn

Introduction to Conservation Agriculture https://www.mahlathini.org/resources/manuals/conservation-agriculture-manual/conservation-agriculture/

No-Till For KwaZulu-Natal's Small-Scale Farming Systems https://archive.org/details/no-till-for-kwa-zulu-natals-small-scale-farming-systems

No-till: Guidelines for beginners This 54-page document is aimed at commercial crop farmers (rather than smallholders) considering conversion to no-till cropping. However, it is included here because it highlights many of the difficulties associated with conservation agriculture and no-till crop production in KwaZulu-Natal. It is available from the No-Till Club of KwaZulu-Natal (the publishers; http://notillclub.com/) and was authored by Aubrey Venter and Ant Muirhead in 2005.

Water harvesting and other technologies
Smallholder Decision Support System - https://dss.mahlathini.org/home

Farmer-managed natural regeneration
Rinaudo, T., Muller, A. & Morris, M. 2019. Farmer Managed Natural Regeneration (FMNR) Manual. World Vision Australia. PDF

Hassan Abdirizak, Masumi Gudka, Benjamin Kibor, Monica Kinuthia, Paul Kimeu, Jan de Leeuw, Malesu Maimbo, Uriel Safriel, Mary Njenga, Miyuki Iiyama 2013. Farmer-managed natural regeneration: How to regenerate pasture and farmland on a low budget. World Agroforestry.

World Vision International 2012 Farmer Managed Natural Regeneration (FMNR) project model. Integrated Ministry & World Vision International. Uxbridge, UK. PDF

Bioirrigation
Bayala, J. and Prieto, I., 2019. Water acquisition, sharing and redistribution by roots: applications to agroforestry systems. Plant and Soil, pp.1-12. DOI PDF This review indicates that hydraulic lift by deep-rooted perennial plants (shrubs or trees) can help to reduce the effect of droughts on annual crop production in agroforestry systems and promote productivity in some regions with erratic rainfall. Precise measurement of the contribution of the various water fluxes in the groundwater-subsoil water-topsoil water-mycorrhizal-root-shoot-atmosphere continuum is fraught with difficulties, but modelling of important parameters may contribute to the design of more productive agroforestry systems for drought-prone regions.

Drought-tolerant crops
Drought avoidance by having a short growing season - mung bean, millet, leafy vegetables, buckwheat http://mccc.msu.edu/wp-content/uploads/2016/09/IA_2016_Short-Duration-Cover-Crops-for-Vegetable-Production-Systems.pdf CAM crops need less water per unit CO2 fixed The potential of CAM crops as a globally significant bioenergy resource: moving from ‘fuel or food’ to ‘fuel and more food’ https://www.researchgate.net/publication/278742016_The_Potential_Of_CAM_Crops_As_A_Globally_Significant_Bioenergy_Resource_Moving_From_Fuel_Or_Food_To_Fuel_And_More_Food Davis 2019 https://doi.org/10.1093/jxb/erz223

Crop modelling
Estes, L.D., Beukes, H., Bradley, B.A., Debats, S.R., Oppenheimer, M., Ruane, A.C., Schulze, R. and Tadross, M., 2013. Projected climate impacts to South African maize and wheat production in 2055: a comparison of empirical and mechanistic modeling approaches. Global change biology, 19(12), pp.3762-3774. DOI PDF

Sinnathamby, S., Douglas-Mankin, K.R. and Craige, C., 2017. Field-scale calibration of crop-yield parameters in the Soil and Water Assessment Tool (SWAT). Agricultural water management, 180, pp.61-69. DOI

Schulze, R.E., 2016. Agriculture and Climate Change in South Africa: On Vulnerability, Adaptation and Climate Smart Agriculture A Selection of Extracts from HANDBOOK ON ADAPTATION TO CLIMATE CHANGE FOR FARMERS, OFFICIALS AND OTHERS IN THE AGRICULTURAL SECTOR OF SOUTH AFRICA Chapters A1, A2, A3, A4, K1 and Appendices. PDF

Schulze, R.E., 2016. On Observations, Climate Challenges, the South African Agriculture Sector and Considerations for an Adaptation Handbook. In: Schulze, R.E. (Ed.) Handbook for Farmers, Officials and Other Stakeholders on Adaptation to Climate Change in the Agriculture Sector within South Africa. Section A: Agriculture and Climate Change in South Africa: Setting the Scene, Chapter A1. PDF

Pest and Disease Control
Natural Pest and Disease Control Handbook Chemical control options for Fall Armyworm in maize https://www.kzndard.gov.za/images/Documents/RESOURCE_CENTRE/GUIDELINE_DOCUMENTS/Research_and_Technology_Bulletin/Chemical-control-options-for-Fall-Armyworm-in-maize.pdf Disease Management in Crops https://www.kzndard.gov.za/images/Documents/researchandtechnologydevelopment/publications/Research_and_Technology_Bulletins/2016.01-Disease-Management-in-Crops.pdf The application of plant based pesticides in sustainable agriculture https://www.kzndard.gov.za/images/Documents/RESOURCE_CENTRE/GUIDELINE_DOCUMENTS/Research_and_Technology_Bulletin/2015.08%20The%20application%20of%20plant%20based%20pesticides%20in%20sustainable%20agriculture.pdf

Weed control
Weed Management Principles For Maize PDF This four-page document discusses the principles of weed control in a maize crop. It indicates the importance of good general agronomic practices to ensure rapid closure of the maize canopy, makes recommendations regarding the use of tillage and mulching and gives guidelines for the use of herbicides.

Vegetable Production In KwaZulu-Natal: Weed Control PDF A three-page document that outlines the importance of weed control in vegetable production and discusses the use of cultural methods and herbicides.

Bezuidenhout, S., 2015, Sprayer calibration. Research & Technology Bulletin 2015/10, KwaZulu-Natal Department of Agriculture and Rural Development. Republic of South Africa, Pietermaritzburg. PDF A four-page document describing how to calibrate agrochemical spraying equipment. It includes sections on nozzle selection, water quality, and details of calculations used to calibrate knapsack sprayers and boom sprayers.

Soil Fertility
Using Manures To Supply Plant Nutrients https://archive.org/details/miles-1998-using-manures-to-supply-plant-nutrients A two-page guide to the use of manures. It includes information on the nutrient content of manures and suggested application rates.

Soil Testing for Better Crops https://www.kzndard.gov.za/images/Documents/researchandtechnologydevelopment/publications/Research_and_Technology_Bulletins/Soil-Testing-for-Better-Crops.pdf A four-page guide to soil sampling and the submission of soil samples for fertilizer recommendations.

Completing the Sample Submission Form https://www.kzndard.gov.za/images/Documents/researchandtechnologydevelopment/publications/Research_and_Technology_Bulletins/Completing-the-sample-submission-form.pdf A pamphlet outlining the information requested when submitting soil samples for fertilizer recommendations.

Crop-specific guidelines
Vegetable Production In A Nutshell https://archive.org/details/allemann-young-1998-vegetable-production-in-a-nutshell Crop-specific guidelines are given for a range of vegetable crops grown in South Africa, along with general fertiliser guidelines. Suitable climate, soil types, cultivars, sowing times, seeding rates, plant population and spacing are outlined, and brief indications are given regarding the required fertiliser, possible pests and diseases, and likely yields. Vegetables included are beetroot, brinjal (eggplant), cabbage, carrot, chilli (hot pepper), trailing cucurbits (butternut, gem squash, hubbard squash, pumpkin), green bean (bush type), green pea, lettuce, amadumbe (taro), onion, potato, sweet pepper, sweet potato, swiss chard, and table tomato.

Brochures and Production guidelines for a wide range of props are available on the website of the South African Department of Agriculture, Land Reform and Rural Development (DALRRD) https://www.dalrrd.gov.za/Branches/Agricultural-Production-Health-Food-Safety/Plant-Production/Production-Guidelines

Important rain-fed (dryland) crops Maize Dry beans Sugar cane Pumpkin Madumbe Sweet potato Irish potato Minor rain-fed crops Cowpea Field pea Dryland leafy greens - Japanese radish, kale, amaranthus, swiss chard Sorghum Millet Vegetables (most need irrigation or water harvesting) Trees for fruit, nuts, medicinal purposes, edible leaves


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Planet Earth/8c. Solutions for the Future

Introduction
Earth does not face any danger, but its inhabitants do. Throughout this book you have been exposed to the realities of science, which is based on the keen observations you can witness from our position in the universe, spinning on this singular planet you were born and live upon. As our only home, solving issues that threaten our long-term ability to continue to occupy this singular place in the universe is of supreme importance. The Earth is changing, its atmosphere becoming enriched in carbon dioxide, the climate growing warmer, the land surface converted to concrete and pavement, and forests cleared for crops with fields of fertilized rows of plants for consumption. Species are becoming extinct at an alarming rate as habitat is lost, but the Earth will continue its rotation, spinning around the sun, whether we are here or not. The changes facing the Earth today are not unique, the Earth’s surface has been subjected to far worst in its 4.5-billion-year history, and will eventually be engulfed in the sun in the far-off future. Humans pose no risk to it. For the Earth, the end is far away, but for the life and inhabitants of the planet, for your continued survival, change is everywhere. Once humans, like yourself are vanquished, you will all leave behind a carbon dioxide rich atmosphere, the plants will flourish, but many other species, including your own, likely will perish. Oceans will be transformed, hard hit by the changing water chemistry and acidification, but they will not boil away. Cities will be either swallowed by great dunes of blowing sand, or torn down by the growth of rooted trees and encrusting vegetation, slowing eroding the manmade landscape you will leave behind. The distribution of refuse left by the exuberant human occupation will eventually become buried and turned to stone. In the short span of 100 million years, nothing but fossilized skeletons and shelled artifacts buried in rock will remain of your once grand occupation of the planet. The Earth will continue to spin around the sun, if life still exists, it will evolve, adapt and change as it always has. The true paradox that we face today, is how to make the Earth a good place for yourself, a place that humans can flourish upon far into Earth’s future.

This is where you came in. By learning more about the Earth and reading this textbook, and by taking this class, you can apply this knowledge to help preserve Earth’s unique place in the universe as our home.

Better Governance
Large campaigns have been launched since the 1960s to rally people to learn of the importance of protecting Earth’s resources for future generations. The establishment of Earth Day in 1970, was one of those efforts. Its roots stemmed from a major ecological disaster in 1969, a massive oil spill that covered the beaches in Santa Barbara California in oil slick extending from Ventura to Santa Barbara north of Los Angeles California. The oil had ruptured through an offshore oil rig, and was unable to be capped or stopped, and continued to leak into the ocean for days. The ocean shore and beaches filled with the toxic oil, killing fish and wildlife across California. Outrage over the disaster compelled two United States Senators to proposed a new initiative to raise public awareness of the environment, and help push for regulations. This effort was initiated by Senator Gaylord Nelson (a Democrat) and Senator Pete McCloskey (a Republican). The effort was to teach people of the importance of Earth and protecting the environment, led by dedicating one day a year to the teaching and educating the public on the topic, and by organizing local groups at many college campuses and universities across the nation. The day of learning extended to high-schools and elementary schools, all focused on learning about the Earth. The Earth Day initiative was led by a young activist and avid backpacker Denis Hayes to lead the project. The Earth Day idea sparked a new national movement to protect the environment, which spread internationally. These initiatives lead to protests and a call to action for citizens to participate in the passage of laws and regulations that guaranteed the safety of the environment and protection of natural regions within the United States. In an amazing flurry of new legislature some of the country’s most important laws that we have today were passed, including the establishment of the United States Environmental Protection Agency.

The Environmental Protection Agency was the first governmental organization to work to protect the Earth’s natural resources, including safeguarding the air you breath and water you drink. The organization was backed by two of the United States most important laws, the Clean Air Act and the Clean Water Act. These two acts focused on the protection of the air and water that you need to live a healthy life. The passage of the Occupational Safety and Health Act, and the outlawing of toxic and dangerous insecticides, fungicides, and rodenticides helped to restore confidence in safeguarding human health. One of the most important laws was the passage of the Endangered Species Act in 1973. This act protects the United States endangered plants and animals, helping to ensure that all species have the required habitat to ensure their survival.

This progress did not come easily to the United States. Lobbyists representing industrial and international corporations have fought bitterly to repeal these laws and to a return to the unregulated dumping of pollution into the water and air as before, without the guaranty of the safety and health of the natural resources that are necessary for human health and happiness. The protection of species has been challenged, as governmental officials continue to be offered brides, and the rules and laws softened to those companies that offer incentives and deals in backroom negotiations. Good governance is essential for the protection and preservation of the natural resources on Earth to continue to support its growing population of humans. But how do you accomplish this?

The governance of a nation must be scientific in its approach. Unbiased by the wild whims of public opinion, superstition and propaganda, and grounded in the collection and support of actual data, and further testing everyone’s assumptions and everyone’s beliefs no matter how frightening or definitive they are to you or your background knowledge. Good governance comes from the acknowledgment of reality that each individual faces as you, your family, your friends, and your loved ones move forward into this unknown future. You get a little voice to say what you want the future of Earth to be like, you should use that tiny voice wisely.

Importance of the Preservation of Lands

Of upmost importance is the preservation of Earth’s surface, and the establishment of agencies for the protection of vast regions on Earth in order to preserve its biodiversity, forests and the natural world that you rely upon for clean air and water, as well as provide beneficial resources for recreation. Only about 3.5% of the United States is protected under an any government order to limit or ban the corporate extraction of resources from the land. The remaining 96.5% of the United States is open to the exploitation of the resources from the land. In fact, this includes about 28% or 2.27 billion acres of land within the United States held in public trust by the United States Government. Most of this land is leased for profit by the federal government in oil and gas extraction that pollutes the air and water. Most of this land is open to mining minerals and coal, as well as the cutting of trees for timber and agriculture. A simple act of Congress could protect 28% of the United States lands in perpetuity for the long-term survival of the country, preservation of the air and water and would be a major benefit to the overall health of the country. Such an act is not impossible, and as the country depletes those resources, the economic incentives to protect these lands increases, as oil and gas fields become uneconomical in the extraction of these resources and only speculative destruction. Individual states manage 9% of the land within the borders of the United States, so together 37% of the United States land can be protected if every state within the union participates – more than a third of the land within the country, but only if governmental officials and lawmakers push to protect these lands by restricting or eliminating leasing programs and subsidies. Such a simple act of congress would limit the production of hydrocarbon producing pollutants into the air by an equal amount.

Other countries also need to follow similar plans to help protect the plants, animals and land within their borders using an international and growing network of national parks and protected lands, with strong enforcement and penalty for the illegal extraction of natural resources. There is great fear that such initiatives will lead to reduce growth, but such endeavors have a long-term benefit that are needed for the long-term survival of the human species.

Rewilding and Biodiversity Protection

The lush tropical cloud forest in the El Cielo Biosphere Reserve in the Mexican State of Tamaulipas is a protected area today, but in the late 1940s Paul Martin clambered through the wet air and vermillion vegetation that over hung moss covered rocks and glass like pools of blue green water. The landscape is a forgotten place, a prehistoric world. To Paul Martin this place was magical, filled with a wealth of colorful flowers, birds, lizards and snakes. With diligent delight he studied the animals, noting their habitat and niches, and how they utilized the natural resources of the landscape in such wondrous ways. These observations he wrote about, documenting the biodiversity of the region, which ultimately helped lead to the landscape’s preservation today. Joining the faculty of the University of Arizona in 1957, Paul Martin begin to study the broader topic of extinction, particularly the recent mass extinction of the late Pleistocene, about 11,000 years ago, when the American continents lost their great megafauna of giant camels, mammoths, mastodons, ground sloths, glyptodonts, and toxodonts, as well as the loss of the American lions, cheetahs and saber-toothed cats, and dire wolves. The prehistoric world that lay just in the desert sands and dirt filled arroyos of the American Southwest. This project became his life’s work, to document the exact ages of the last appearance of these iconic extinct animals of the American continents and determine how they went extinct. Using radiocarbon dating, Paul Martin’s work revealed something profound – the extinction of these large mammals was parallel to the arrival of humans. The theory he proposed became known as the Overkill Hypothesis. The Overkill Hypothesis theorizes that over hunting and the human exploitation of these large iconic animals of the recent past, lead to their ultimate extinction. Further dating and refinement of the studies have continued to show strong support for the idea, particularly when small mammals, such as rodents show no such extinction during the recent past (last 25,000 years ago). This idea that humans drive extinction of large mammals, particularly of prey animals which are a food source and hence important to early human hunters on the Americans continents, such over hunting and over harvesting of natural resources has deep roots in human history. Paul Martin’s work pushed the enormous responsibility for the preservation of today’s existing animals and plants onto better restrictions and limits on hunting and harvesting, eliminating the threats posed by overkilling and over harvesting plants and animals that naturally exist on the landscape. Today’s elephants, rhinos, giraffes, wildebeest, bison, moose, and elk all can be easily overexploited to extinction. When Paul Martin looked out across the vast American landscape he saw the ghosts of the animals that once called this place their home. In 2005, shortly before his death, Paul Martin wrote about his brave and ambiguous idea of a great rewilding of America. He proposed establishing great reserves and protected parks across the United States of America where animals and plants could grow and prosper, with the introduction of large iconic animals, and wild parks to support these herds. Paul Martin saw a future and glorious country that could support these great creatures in healthy landscapes with a return to a wilderness state of existence for a portion of the Earth’s surface.

Solar Power and the end of Hydrocarbon Use

The greatest threat to human existence today is the rapidly changing atmosphere of Earth. Not only does the rise in carbon dioxide gas result in an increasingly and rapidly warming Earth, it also effects ocean chemistry and the breathability of the air necessary for animals to survive on the planet. The rapid rise of human hydrocarbon energy use within the last century has also led to a profound change to the Earth’s surface by the vast network of roads, highways, parking lots and pavement that has increasingly covered more of the Earth’s terrestrial surface. These gray zones of urban landscapes can be seen from outer-space, as gray blotches emanating from city centers into long tangled threads of highways and roads.

Acknowledging the problem has led to a wealth of novel solutions, particularly in the realm of technology applied toward electric motors, batteries, energy storage and energy sourced from the sun. Solar energy is a more readily available resource for energy, because it is renewable, and consistent during the day, enough to be harness for energy needs. The challenges facing this end to hydrocarbon usage comes from the challenge of both capturing this energy, but also storing the energy for long term usage. There will be energy loss in the transfer of energy from one state to another, but using the flow of electrons from excited photoelectric cells, and storing that energy in chemical form, still has great potential at reducing, and maybe even eliminating hydrocarbon usage in the near future. As hydrocarbon fuels become more expensive, there will be a trend away from their use as an energy source, particularly in combustion engines. A simple carbon tax has been proposed, that would push greater adoption toward electronic motors, and renewable energy. The United States Energy Information Administration estimates that only 12% of the country’s energy comes from renewable sources, with 8% from nuclear power, leaving 80% from hydrocarbon combustion, including the burning of petroleum liquids, coal solids, and methane and other hydrocarbon gases. Transportation and industrial energy usage in the United States accounts for 72% end usage, where as residential usage is only 16% of the energy consumption within the country.

The replacement of combustion engines with electric engines running on batteries for transportation would dramatically decrease the usage of hydrocarbon fuels, if the energy source for these electric engines are from renewable energy sources like solar and wind. Nuclear energy also holds great promise because it does not emit carbon dioxide pollution in the generation of electricity. Batteries that are also reusable, through deep cycling of electron transfer and the recycling of battery components also eliminate the necessary large-scale consumption of natural resources necessary for hydrocarbon usage that requires the burning of material to derive energy from it, that cannot be reused once the energy is released. A decrease, and eventual elimination of the usage and reliance on hydrocarbons like petroleum and coal would have a positive effect on the habitability of Earth.

Recycling and Waste Reduction

It may sound odd, but landfills might become new mining opportunities for resource extraction as they contain higher levels of resources that are becoming scarce in the natural world, but this requires the separation of hazardous materials, and the grouping of disposable waste into categories for recycling and proper disposal. Reusing material, including metals, glass, and plastics has the potential to become more and more economically important as traditional raw sources of metals, glass (silica) and plastics become more prohibitive and expensive. The reusability of waste must be encouraged. Packaging taxes and regulations can help reduce both cost and the production of useless waste. Oversight on packaging of products can eliminate much of the cardboard and plastic waste that comes from the everyday products that we purchase. This does not mean that packaging is completely eliminated with food and drink products, but these waste producing materials must be justified and overseen by better governance and regulated, with specific ways to reduce and reuse the packaging of products produced by companies. Recycling cardboard packaging would go a very long way in reducing deforestation, and providing sustainable forests. Currently it is estimated that about 1 billion trees are needed to supply the annual usage of cardboard in the United States, which is equal to 7 trees per American per year. Reduction of cardboard packaging, and recycling is essential, as this all adds up in the unnecessary waste of valuable natural resources, particularly the Earth’s forests and trees. The advent of shipping products and materials of internet purchases places great demand of cardboard, much of which is never recycled, and ends up in landfills or dumped in the ocean. According to a 2017 study by the Environmental Protection Agency (https://www.epa.gov/facts-and-figures-about-materials-waste-and-recycling/paper-and-paperboard-material-specific-data), the amount of recycling of cardboard rose from 17% to 67% between the years of 1969 to 2017, yet the total needed annual raw sourced cardboard from the cutting of trees was still nearly 22.7 million U.S. tons of cardboard that comes from forests. As more forests are protected, sources of cardboard and paper products will need to come from recycled materials, or materials that can be reused more efficiently. Reusable shipping boxes should become the norm, as more products are shipped between cities and towns.

Sources of phosphate, nitrogen (ammonia), and potassium used in fertilizer today often is sourced from raw ore or sediments rich in these elements, however many of these sources will soon be depleted or restricted for open pit mining or strip mining at current consumption levels, resulting in more expensive fertilizers and diminishing returns on crops. One of the key changes that will be necessary is for the growth in the manufacturing of fertilizer from human waste and sewage. Raw sewage is rich in these elements, which can be captured and recycled, cleansed of bacteria and viruses and used as a fertilizer on crops. Capturing these nutrients is also important in the preservation of freshwater, and prevention of eutrophication in freshwater lakes and rivers. Every city will need to put together the infrastructure to be able to process the waste and reuse the extracted phosphate, nitrogen and potassium for agriculture use.

Energy Efficiency

Energy efficiency is one of the easiest ways to reduce the consumption of energy sources, like hydrocarbon fuels. Regulation on the miles per gallon of motorized vehicles leads to greater savings on consumers and users of automobiles, but also dramatically decreases the costs to operate vehicles used in transportation. Energy efficiency can also draw down the cost of heating and cooling buildings, as well as electric appliances and machinery. Energy efficiency often is rapidly enhanced in products when the refueling costs dramatically increase, such as after the peak oil years of the early 1970s, that saw more fuel-efficient vehicles dominate the market. From an economic laissez faire capitalism view energy efficiency requires little oversight by governance, rather it can organically come about as resources become depleted or too costly for the operation of the equipment. The cost of a car today is less than the cost of the fuel that is required to run the machine throughout its life, as new electric or hybrid engines become increasing standard, these re-fueling costs could make transportation much more affordable, while also reducing air pollution in urban centers, and reducing carbon dioxide emissions. Fuel emission standards are important because they can help in the transition to new technology and innovative products.

Summary
In order to make Earth habitable and a place for the future success of humans, major transformations in the interaction between humans and the Earth’s resources need to happen. First through better governance and the elimination of corrupt elected officials and appointed agents of the government. Second the end to appropriations and leasing of publicly owned natural resources to private companies for profit and exploitation, and the preservation of lands with strict limits or elimination of these exploits. By protecting a third of the land on Earth, forests can be filled with trees and plants that will help to capture and reduce carbon dioxide, bring back the wilderness, reduce extinction, and slow the process of climate change. Third protecting wildlife, and introducing native plants and animals, a portion of the Earth can return to a more wild and natural state that would benefit human survival on the planet. Forth is the push to reduce and eventually eliminating hydrocarbon fuels and replace them with renewable sources of energy such as solar, wind and nuclear. Use of electric motors, or hybrid energy efficient motors, rather than antiquated combustion engines will help reduce emissions of carbon dioxide, and restore the atmosphere of the planet. Technology now exists to make this more standard. Fifth, the reuse and recycling of paper products and other waste to make up for the raw resources as they become depleted and as public lands become areas set aside for the preservation of the landscape. Sources for these materials will have to come from the reuse and recycling of these materials. With only five simple actions, the Earth can be transformed into a more sustainable place for human habitation.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


text: Mirad Grammar/print version

title: Mirad Grammar/print version


text:
Wikibooks:Reading room/Administrative Assistance/Archives/2020/June

History merge needed
Exact copy-paste: https://en.wikibooks.org/wiki/Special:ComparePages?page1=&rev1=1180912&page2=&rev2=1181104&action=&diffonly=&unhide=

Revisions up to Special:Permalink/1180912 at Hebrew/Aleph-Bet5 should be moved to Hebrew/Aleph-Bet/5.

Thanks, --DannyS712 (discuss • contribs) 07:28, 22 February 2020 (UTC)
 * The bot just archived with after no response - hello? Can anyone do this? Thanks, --DannyS712 (discuss • contribs) 13:31, 12 April 2020 (UTC)
 * Was just archived a second time. Pinging the admins:        sorry for the mass ping, but the request for an easy hist merge has been open for over 3 months with no response. Can one of you please take a look? Thanks, --DannyS712 (discuss • contribs) 08:39, 2 June 2020 (UTC)
 * Sorry, it's done now. Thanks - QuiteUnusual (discuss • contribs) 08:57, 2 June 2020 (UTC)
 * Thanks. A couple more if you can take a look
 * Special:PageHistory/Hebrew/Aleph-Bet1 -> Special:PageHistory/Hebrew/Aleph-Bet/1
 * Special:PageHistory/Hebrew/Aleph-Bet2 -> Special:PageHistory/Hebrew/Aleph-Bet/2
 * Special:PageHistory/Hebrew/Aleph-Bet3 -> Special:PageHistory/Hebrew/Aleph-Bet/3
 * Special:PageHistory/Hebrew/Aleph-Bet4 -> Special:PageHistory/Hebrew/Aleph-Bet/4
 * Special:PageHistory/Hebrew/Aleph-Bet6 -> Special:PageHistory/Hebrew/Aleph-Bet/6
 * Thanks, --DannyS712 (discuss • contribs) 09:00, 2 June 2020 (UTC)
 * All done - thanks - QuiteUnusual (discuss • contribs) 09:08, 2 June 2020 (UTC)
 * My apologies for missing this. Nice to see QuiteUnusual do this already. Leaderboard (discuss • contribs) 13:39, 2 June 2020 (UTC)

Access to deleted history
A long time ago, I transwiki'd a number of pages to another wiki before they were deleted here. That wiki is preparing for the actor migration, and I'd like to make sure the contributions imported from wikibooks are properly associated with the appropriate users from here. With many of the users renamed here, and many of the contributions deleted, it's quite difficult to piece together which edits came from here. Is there some way I can get read-only access to view deleted contributions? I have approximately 3000 users and 20,000 edits to reconnect, so going page by page would be difficult. -- Prod (discuss • contribs) 09:46, 31 May 2020 (UTC)

 * Hello, a vote could allow you to be administrator during one week, for this task only. JackPotte (discuss • contribs) 13:16, 31 May 2020 (UTC)

 * I doubt that this would get community support as it would give unrestricted rights which could only be stopped by a Steward (as we can't remove +sysop locally). There's no problem with users being renamed here - it is still possible to trace the attribution back to the original user. QuiteUnusual (discuss • contribs) 09:01, 2 June 2020 (UTC)
 * All the pages that they contributed to have been deleted. For example, this user has 100+ edits that were transwiki'd before the pages were deleted here. -- Prod (discuss • contribs) 14:57, 2 June 2020 (UTC)
 * Another example is User:The/User:The~enwikibooks. This user has a dozen edits on my site, but none of them show up here. I don't really see any logs that mention the user was renamed here. -- Prod (discuss • contribs) 00:16, 3 June 2020 (UTC)

112.133.232.85
Please see Special:Contributions/112.133.232.85 - vandalism --DannyS712 (discuss • contribs) 05:39, 6 June 2020 (UTC)
 * ✅ JackPotte (discuss • contribs) 07:31, 6 June 2020 (UTC)

Vandalism
Please block this ip --Samuele2002 (discuss • contribs) 01:10, 13 June 2020 (UTC)
 * I did give them a local block, as a matter of form and for the record, though it's redundant to a longer block already placed on them globally. --Pi zero (discuss • contribs) 03:08, 13 June 2020 (UTC)


text:
Wikibooks:Reading room/Archives/2020/June

== 🎨 Styling catlinks (category links at bottom of each page) for all readers of a book as an author-side customisation (rather than as a reader-side customisation) ==

The category links at the bottom of each page com under the undefined element. Have been trying to figure out how to style the contents for all users of a book (at least as the default skin for users, something like a 'book skin') but have had no success in figuring out how to do it, and not sure whether it is even possible.

Things tried (but were not successful) :

 * templates styled with CSS file styles.
 * removing the default catlinks so new ones could be drawn-up.

Anyone have any ideas or comments on solving this?

 * What sort of customization are you trying for? The cat list at the bottom of the page is, after all, part of the site customization, so I'm dubious whether it ought to be customizable per book; but I'm open to being persuaded. --Pi zero (discuss • contribs) 17:21, 28 May 2020 (UTC)

 * for what it's worth, I'm also dubious. 😕

 * I would like each category to be on a separate line. A bullet-pointed vertical list would be acceptable, and I think one of the skins does this already. But the skins are set-up as user skins rather than book skins—I was hoping to use something like a book skin. Also, I do not want the text 'Book:End-user Computer Security' to appear at the beginning of each item, as it makes the category links difficult to read. If it were '📘' instead, that would be okay.

 * I have similar issues with the category pages. I'm thinking perhaps it might be best to create a user skin, that also has the meaning of being a particular skin for the book, and then somehow advertise or advise to users, that the book is best used with the particular book skin developed for the book. What do you think about that? As you imply, overriding the controls that prevent author-side customisation of the links is perhaps not a good idea.
 * I never tinker with skins, myself. It occurs to me to mention, iirc we have a provision in our infrastructure for book-specific css. Possibly something could be done with that.  (I don't often tinker with css, either, but have occasionally done so.) --Pi zero (discuss • contribs) 17:47, 1 June 2020 (UTC)
 * that sounds like it might be a good idea. I've already looked at how CSS (including CSS files) can be used on the author-side (i.e. on a book-specific basis), but couldn't get it to work, as the styling was unable to style that part of the page (the part that required styling was outside the scope). Just so that I can be clear about what you mean by Wikibook's provision for book-specific css, can you please post a link to the documentation for it?
 * I'm not sure there is any documentation. I know about it because of my work on the dilaog tools, which depend on a related device (per-page javascript, originally a Wikinews thing); along the way I discovered Wikibooks has per-book css, supported by MediaWiki:Common.js/Perbook.js. --Pi zero (discuss • contribs) 14:59, 2 June 2020 (UTC)
 * that's looking like what I'm after. So if I create a file at 'https://en.wikibooks.org/wiki/MediaWiki:Perbook/End-user_Computer_Security.css', will that CSS file automatically be used in the End-user_Computer_Security book? Currently, it's saying I don't have permission to create the page at that address. Any idea what I should do?
 * I think I have the requisite priv to do that. If you set up the content you want in a page in, say, your userspace, and tell me where it is, I can look it over and (if it looks okay, of course) I can set it up for you. --Pi zero (discuss • contribs) 15:47, 2 June 2020 (UTC)
 * any chance you could set-up a SANDBOX where I can experiment with such code (presumably with a SANDBOX book)? The reason I ask, is that as mentioned before, I'm not able to style the CATLINKs section otherwise (as far as I can tell); so it's a bit difficult to develop the needed CSS code without using the specific book-skin resource (with which I hope to be able to style the CATLINKs).
 * A sandbook? :p Hopefully I can try to set something up later today (though I can't guarantee, as my plate is pretty full atm). --Pi zero (discuss • contribs) 16:05, 2 June 2020 (UTC)

Trying to replace tags with   tags,   with  ,... and so on....
I want to do this so that the transcluded headings in a transcluded text, are all dropped down by one level, such that the table of contents then appears correctly structured.

Found the  function, but just can't get it to replace particular digits. Have a feeling that perhaps I need to do some character escaping to communicate string literals, but have tried all kinds of things for this with no success. Anyone have any ideas/advice?

 * Not sure concretely what you're trying to do. Is there a specific example one can look at? --Pi zero (discuss • contribs) 12:16, 3 June 2020 (UTC)

 * have a look at the table of contents at Category:TODO/End-user_Computer_Security_book. That page uses transclusion, and I wanted the heading levels for the headings in the transcluded text to be demoted by one, so that I could add some more intervening parent headings. The way I figured out for doing this, was to replace '== ' with '=== ' and ' ==' with ' ==='. But then it seemed that after transclusion, the equals notation was converted into HTML notation for headings (i.e.,  , etc.) So then I was looking at replacing the text 'h1' with 'h2', but I couldn't get it to work with the aforementioned function. I managed to replace just the 'h' character, but I also need to replace the digit character as well. If you could give me one example of how to use the function to replace digits, that would probably be a step in the right direction.

 * I'm not a believer in lots of non-wiki-markup tools for specialized purposes, which tend to multiply as one finds new tasks one wants to perform. Basically the only purpose for which I use Lua/javascript is (by preference) to provide highly general tools that enable everything else to be done in wiki markup.  In this case, I would go about what you're describing using evalx, my general "glue" tool for doing things that fill in awkward gaps in what can be done without them.  No doubt this is less efficient than using the highly specialized Lua tool you're describing.  I'd probably write a little book-specific template, something like this (supposing one only had to replace headings down to h4):

 * Does this actually work, since I wrote it freehand? I'd probably test it on the Breadboard (being careful to pass in, as the value of parameter 1, expanded html rather than raw wiki markup); apologies that I haven't done so, 'fraid I'm kind of strapped for time just atm. --Pi zero (discuss • contribs) 17:01, 3 June 2020 (UTC)

 * thanks for this possible solution. My priorities have changed now such that I'm not going to bother trying to solve this problem for the time being. I don't know how Wikibooks archives such reading-room issues, but it would be good if this question-answer, problem-solution topic was archived in the collective Wikibooks knowledge-base, for easy retrieval by ppl later on.

Collapsible block:    just some thoughts of MarkJFernandes concerning best coding practices for Wikibooks Understand where you're coming from when you talk about many '...non-wiki-markup tools for specialized purposes...'. Being a Wikibooks newbie, I tend to follow the philosophy that newbies should learn as they go along. This might mean overly using CSS and HTML, and gradually transitioning more and more to pure wikitext. I would apply this also to the use of non-wiki-markup tools for specialized purposes. I think along the lines that it is better resource management than delaying contributions until you are proficient in Wikibooks technology; others can always help you along the way, and in terms of the totality of resources consumed (by the whole community together), I believe it leads to less resource consumption.

Trouble adding book images to BOOK SUBCATEGORY
Can't figure out how to CATEGORISE my book images in my images BOOK-CATEGORY SUBCATEGORY.

Can someone please direct me as to how I can get, to be CATEGORISED in my images BOOK CATEGORY? I tried to do such CATEGORISATION in the edit shown, but it didn't work.

 * Nothing you do to the page on Commons will affect categorization on Wikibooks. I think you can create a local description page on Wikibooks containing nothing but the requisite book category, and that'll do it.  If I'm remembering rightly (someone on Wikinews discovered this a bunch of years ago and was quite charmed by it), and if it still works now (if it ever did). --Pi zero (discuss • contribs) 09:08, 4 June 2020 (UTC)

 * Nope, it doesn't want to allow that; if it ever did work, it seems not to anymore. Or maybe I'm just not doing it right. --Pi zero (discuss • contribs) 09:12, 4 June 2020 (UTC)

 * Hm. It looks like it should work.  Cf. n:File:Ellie Cole.jpg. --Pi zero (discuss • contribs) 09:19, 4 June 2020 (UTC)

 * Okay, I think I've got it now. The trick is to avoid the "do what somebody else thinks you should want to do" interface.  Viewing the local page, I edited the url in the browser tab and added  to the end of it, then hit <enter>, and put in the page
 * --Pi zero (discuss • contribs) 09:35, 4 June 2020 (UTC)
 * --Pi zero (discuss • contribs) 09:35, 4 June 2020 (UTC)

 * superb! Just read this. Someone probably should report this bug somewhere?

 * I would be concerned, pessimistically, that if their attention were drawn to it they'd "fix" it in a way that would only make it harder (or impossible) for us to accomplish what we want to do. --Pi zero (discuss • contribs) 17:59, 8 June 2020 (UTC)

RFC affecting WikiBooks on MetaWiki
Hello! I've started an RFC on MetaWiki about what I see as overlap between Wikiverity and Wikibooks, specifically in the area of foreign language learning, where there are virtually identical resources (with lessons, exercises, etc.) on both platforms. I wanted to post here to get feedback from those with more experience/investment in Wikibooks. Link is below:

RFC on MetaWiki

--Chapka (discuss • contribs) 14:18, 17 June 2020 (UTC)

Editing news 2020 #2
Read this in another language • Subscription list for this multilingual newsletter

This issue of the Editing newsletter includes information the Talk pages project, an effort to help contributors communicate on wiki more easily.

 * Reply tool : This is available as a Beta Feature at the four partner wikis (Arabic, Dutch, French, and Hungarian Wikipedias). The Beta Feature is called "".  The Beta Feature will get new features soon.  The new features include writing comments in a new visual editing mode and pinging other users by typing  . You can test the new features on the Beta Cluster now.  Some other wikis will have a chance to try the Beta Feature in the coming months.
 * New requirements for user signatures : Soon, users will not be able to save invalid custom signatures in Special:Preferences. This will reduce signature spoofing, prevent page corruption, and make new talk page tools more reliable.  Most editors will not be affected.
 * New discussion tool : The Editing team is beginning work on a simpler process for starting new discussions.   You can see the initial design on the project page.
 * Research on the use of talk pages : The Editing team worked with the Wikimedia research team to study how talk pages help editors improve articles.  We learned that new editors who use talk pages make more edits to the main namespace than new editors who don't use talk pages.

– Whatamidoing (WMF) (talk) 20:36, 17 June 2020 (UTC)

Some advice on plan for final touches on making completed book publicly available?
hello (& hello to other readers), you previously sent me a message offering kind assistance on finally transferring my book to the main public work-space. I've tried to figure out what needs to be done by looking through the Wikibooks help, but not so sure that I've made no mistakes in my planned course of action. Could you,  or even other people , please advise as to whether my following plan of action appears to be correct?

 First run MovePage tool shown here on every page of the book. ✓ OKAYED BY Mrjulesd.   ADD "BOOK CATEGORY" INFORMATION  Add  to the bottom of every page of book other than the main page, as well as to every book template. ✓ OKAYED BY Mrjulesd.  For each image in book, add  to the bottom of the Wikibooks page for the image (the page here is an example of such a page). ✓ OKAYED BY Mrjulesd. Is this the case even for images that may be reused in other book projects? Mrjulesd seems to say 'yes'.   For each talk/discussion page of book, add to the bottom of the page. NOT NEEDED  💬 Mrjulesd. Is this right? Mrjulesd says it's not needed.

 ADD "SHELF AND SUBJECT CATEGORY" INFORMATION

 Place  at bottom of main page of book. NOT NEEDED
💬 Mrjulesd.

Place  at bottom of main page of book. ✓ OKAYED BY Mrjulesd.
 DECIDED TO ALSO ADD BOOK TO ENGINEERING SHELF AFTER HAVING READ THE SHELF'S DESCRIPTION.

 ADD "NON-SUBJECT CATEGORY" INFORMATION   USE  Wikibooks Stacks,   ADD   CCO Resources  ⇒  MAIN PAGE
💬 Mrjulesd.

Add  to bottom of every page of book, where Categories is the specific name of the NON-SUBJECT category into which the page should be placed. When the page should be added to more than one category, add this code more than once, with each instance being for a different particular NON-SUBJECT category under which the page should be classified. The code just mentioned, should be adapted for certain pages of the book; specifically, the  magic word in the code ought to be appropriately exchanged for other text in each such instance; the specific adaptions are outlined in the next list item (b). PROBABLY UNNECESSARY.
💬 Mrjulesd.

For each of the following pages, instead of using the magic word  for the sort key, the special sort key indicated in the table for the page, should be used (default sort key is overridden in such cases): PROBABLY UNNECESSARY.
💬 Mrjulesd.

 After more or less exhaustively examining the present NON-SUBJECT categories, I have determined that I will likely be using the following NON-SUBJECT categories:

Intermediate reading level

Advanced reading level

Books_containing_original_research

 CREATE YOUR CATEGORIES BY CLICKING ON THE RED LINKS IN THE CATEGORIES NAMESPACE.
💬 Mrjulesd. CAN CATEGORISE ON AN INDIVIDUAL-PAGE BASIS (RATHER THAN JUST ON A BOOK-WIDE BASIS), I ADVISE THAT YOU USE SUB-CATEGORIES OF THE BOOK CATEGORY FOR SUCH   (EG. "Category:Book:End-user Computer Security/Whatever").
💬 Mrjulesd.

 Add the presently unfinished book index (only part of book that is currently incomplete), to a new category under the TODO parent category. PROBABLY UNNECESSARY.
💬 Mrjulesd.

 Create "TODO/Index for End-user Computer Security book" as a Category page. Then add following to page:
 __HIDDENCAT__

 Then add the following text to the talk page for the book:

Add the following code to bottom of the book's main page:

✓ OKAYED BY Mrjulesd.

MarkJFernandes (discuss • contribs) 13:01, 22 May 2020 (UTC)

 * That's essentially it. I'll direct you to CCO Resources and Template:BookCat which better explain things than I could probably do.
 * But in summary:
 * Point 1: correct
 * Point 2: yes add BookCat. I imagine your book will be called "End-user Computer Security", so it would add to "Category:Book:End-user Computer Security". Categories to images can also be added by "Category:Book:End-user Computer Security/Images", and templates to "Category:Book:End-user Computer Security/Templates". Talk pages don't need cats, as the parent pages should already have cats.
 * Point 3: shelves is sufficient. I think Subjects came before Wikibooks Stacks came into operation, so is now legacy.
 * Point 4: Firstly please don't add your pages to "Category:Categories". Basically what you need to do is use Wikibooks Stacks; it works very well in practice, and is now the default for books on this project; further categorization could be done but is probably unnecessary. It's also very simple: all you needed to do is add BookCat to each (non-talk) page, and the CCO Resources to the main page. You also need to create your cats by clicking on the cat red-links and clicking create. All the rest is done automatically. You could further categorize pages within your book, but I would suggest you use subcats of the book cat, which I would imagine would be "Category:Book:End-user Computer Security", so something like "Category:Book:End-user Computer Security/Whatever".
 * Point 5: correct.
 * Overall my advice is to keep it simple at this stage, and move on to more advanced things later. Thanks to Wikibook Stacks, its all incredibly simple to get going, and is all you need to do for now. -- Jules (Mrjulesd) 14:46, 22 May 2020 (UTC)

🙏👍
 * was just wondering whether you could advise as to the categories selection part. So what I've done, is that I've gone through all the categories, in the categories namespace, and selected the following rough list of categories that might be appropriate:

 • Business

 • Business/all books

 • Business software

 • Business software/all books

 • Chrome users

 • CodeCook/Tasks/Programming

 • Communication/all books

 • Computer engineering/all books

 • Computer hardware

 • Computer hardware/all books

 • Computer software/all books

 • Computer software by operating system

 • Computing/all books

 • Creative Commons Attribution-ShareAlike images

 • Cyberwarfare

 • DIY

 • Dementia

 • Department:Computing

 • Design

 • Engineering

 • Enterprise Linux distributions

 • Firmware

 • Firmware/all books

 • Greek language

 • Information security

 • Information security/all books

 • Information technology

 • Information technology/all books

 • Internet

 • Internet/all books

 • Internet security

 • Issues in Digital Technology in Education

 • Linux

 • Linux/all books

 • Live distro and Full Linux Install

 • Maintenance and repair

 • Maintenance and repair/all books

 • Media files

 • Military strategy

 • Nanotechnology

 • Nanotechnology/Templates

 • On spies and stratagems

 • Open Source

 • Open source

 • Open source/all books

 • Open source software/all books

 • Operating systems

 • Operating systems/all books

 • Outsourcing

 • Phonetics

 • Photography

 • Photography/all books

 • Photography Equipment

 • Physics

 • Printing

 • Privacy

 • Probability

 • Probability Theory

 • Probability and statistics

 • Probability theory

 • Programming

 • Programmers

 • Programming Languages

 • Risk

 • Security Architecture and Design

 • Semiconductor Electronics

 • Shelf:Wireless communication

 • Shelf:Wireless communication/all books

 • Shelf:Written communication

 • Shelf:Written communication/all books

 • Signal Processing

 • Software engineering

 • Software engineering/all books

 • Statistics/Images

 • Systems Analysis and Design

 • Telecommunication

 • Telecommunication/all books

 • The Written Word

 • Tools and equipment

 • Written communication

 • Written communication/all books

 * Can you just comment on this? Does it look right? Am I perhaps not doing something quite right?

 MarkJFernandes (discuss • contribs) 11:12, 26 May 2020 (UTC)

 * OK I'll tell you what you need to do (at this stage anyway):
 * * In your book click on the category red-link at the bottom of a page, i.e. Category:Book:End-user Computer Security. To this page add two templates: Book category header and BookCat. Put in an edit summary "create" and then press "publish page". You're essentially done with cats at this point, although you could create subcats at some point, depending on how you feel about it.
 * * To the main page, i.e. End-user Computer Security, you need to add the following:
 * **  - this is a suggestion, you may feel other shelves more appropriate
 * **  - if complete, otherwise something else
 * **  - I would imagine that this is roughly right, if you disagree that's fine
 * Now I realise that you've put your main page as a speedy delete, so it may not be possible to do it at this point. But these are the first steps, once you've done this you can think about more advanced options. But for many books this is all you need. -- Jules (Mrjulesd) 16:01, 26 May 2020 (UTC)
 * Now I realise that you've put your main page as a speedy delete, so it may not be possible to do it at this point. But these are the first steps, once you've done this you can think about more advanced options. But for many books this is all you need. -- Jules (Mrjulesd) 16:01, 26 May 2020 (UTC)

 * the book is virtually ready to announce to others. In fact I can announce it even now. There is just one outstanding issue, and that is to do with my images being CATEGORISED in my IMAGES BOOK-CATEGORY SUBCATEGORY. I tried to follow yours and Wikibook's guidance, but am not getting it to work. Can you please direct me as to how I can get this image, to be CATEGORISED in my images BOOK CATEGORY?

 * Ah that's a good question, since its uploaded to Commons it may not be possible. This edit didn't work. Maybe ask at Reading room/Technical Assistance, as there might be a way that I don't know about? But if it's not added to the cat it shouldn't matter too much. -- Jules  (Mrjulesd) 15:37, 3 June 2020 (UTC)

Followed Mrjulesd 's advice, and posted query to the Technical Assistance reading room  here.

Is it not okay to CATEGORISE chapters in non-BOOK, non-SUBJECT/SHELF categories?

 * thanks for your guidance thus far. I've created and used all of my BOOK CATEGORIES, and I'm happy with them for the time being. I'm slightly confused as to whether it is correct or not, to CATEGORISE chapters in non-SUBJECT categories (non-SHELF categories) that are also not BOOK CATEGORIES. Your guides seem to say that you shouldn't do that, and that instead chapters and other non-front-page pages should instead be categorised into BOOK CATEGORIES under the BOOK CATEGORY for the overall book. I know it's probably not necessary at this stage to do any such further CATEGORISATION, but once I've finalised the book, I'm not sure when I'll be returning to it for further improvements, so it might be best to get it out of the way now.
 * well in general that shouldn't be necessary, but I suppose it might depend on the category you have in mind. Have you got a specific example of why this might be necessary, and an example of a category you wish to add chapters to? Sometimes chapters get automatically added to categories like Category:Pages using deprecated source tags through the use of templates. -- Jules (Mrjulesd) 10:06, 3 June 2020 (UTC)
 * We don't use non-book, non subject categories, for example to group pages in different books together. That's because books are seen as independent self-contained things, and one page of a book wouldn't be grouped with one page from a different book. Occasionally people try to do this - usually Wikipedia editors - by adding article type categories, but someone else usually removes them very quickly. QuiteUnusual (discuss • contribs) 10:45, 3 June 2020 (UTC)
 * thanks for both of your responses. I'm going to go with QuiteUnusual's thinking, as this seems to make the most sense to me given what I found in the published guidance, and what QuiteUnusual said about what happens when ppl violate the rule.

Wrestling
I want to start a new book. What do I do? Gorozigg64 (discuss • contribs) 15:58, 9 June 2020 (UTC)
 * Hi,  We provide a book about this, Using Wikibooks. --Pi zero (discuss • contribs) 17:20, 9 June 2020 (UTC)

contribution
Hi. Here is a link. Here 3DickUlus writes: "wiki books doesn't give me the freedom I need to maintain it properly ... they complain when I post a screenshot and tell me that I'm not allowed to post copyrighted material...FragM is opensource and I have contributed more than half of the code, so wikibooks is not the place I want people going for proper and up to date documentation." What do you think about it ? --Adam majewski (discuss • contribs) 19:05, 25 June 2020 (UTC)
 * FragM is a redlink, so I have no clue what the guy is talking about. Can you please be more explicit about exactly what the problem is? —Justin ( koavf ) ❤T☮C☺M☯ 19:35, 25 June 2020 (UTC)
 * Thx for replay. I have updated a link. I have also strikeout some text because it is IMHO normal. Only second part of his comment shows the problem--Adam majewski (discuss • contribs) 16:43, 26 June 2020 (UTC)answer


text:
CLEP College Algebra/Functions

In math, it is often important to describe how a certain set of input from some certain operation can at some point represent the output of such operations. The tool math has created for this regard is called the function. The formal definition of a function can perhaps be a very tricky obstacle to grasp fully, and the best way to understand it is to perhaps use the intuitive concepts in practicum (as a preliminary step towards the goal, understanding). Therefore, we will begin this chapter by giving an intuition behind the processing.

The Intuitive Uses and Definition of Functions
You can think of a function as a kind of machine. You feed the machine raw materials (as an input), and the machine changes the raw materials into a finished product (the output). Let us describe a cook as a function. Handing a piece of lettuce to the cook would result in chopped lettuces as the output. The output is minced lettuces. A function in mathematics is somewhat equivalent. This viewpoint can get us far enough to at least understand its real-life applications.

Think about dropping a ball from a bridge. At each moment in time, the ball has a velocity, $$\mathbf{v}$$. The velocity of the ball is a function of time. This type of function is called real-valued since the "finished product" is a number (or, more specifically, a real number).

Imagine the mean temperature of a river deviates everyday by $$4^{\circ}\text{ F}$$. If the temperature of the river is sampled everyday, with $$n=30$$ samples per day, and the population mean of all the samples collected is $$\mu$$ while the deviation $$\sigma=4^{\circ}\text{ F}$$, then one way we can reflect the distribution of the temperature of the river is by using the Normal (or "Gaussian") function, which is written here below:
 * $$\varphi(x)=\frac{1}{\sigma\sqrt{2\pi}}e^{-\frac{1}{2}\left(\frac{x-\mu}{\sigma}\right)^{2}}$$

If instead, the river only ever deviates $$4^{\circ}\text{ F}$$ from the mean, then one could write it in terms of absolute values:
 * $$|x-\mu|=4=T(x)$$

Either way, a function is used in everyday life.

Think of a real-valued function as an input-output machine; you give the function an input, and it gives you an output which is a number (more specifically, a real number). For example, the squaring function takes the input $$4$$ and gives the output value $$16$$. The same squaring function takes the input $$-1$$ and gives the output value $$1$$.

There are many ways which people describe functions. In the first example, a verbal descriptions is given (the height of the ball above the earth as a function of time). In the second example, some different operations of certain functions are given. The specifics of using operations to describe functions are given below: When a function is given a name (like in number 1 above), the name of the function is usually a single letter of the alphabet (such as $$f$$ or $$g$$). Some functions have names that are multiple letters (like the sine function $$y=\sin(x)$$.
 * 1) A function is given a name (such as $$f$$) and a formula for the function is also given. For example, $$f(x)=3x+2$$ describes a function. We refer to the input as the argument of the function (or the independent variable), and to the output as the value of the function at the given argument. (Note: more on this notation is described in the next section.)
 * 2) A function is described using an equation and two variables. One variable is for the input of the function and one is for the output of the function. The variable for the input is called the independent variable. The variable for the output is called the dependent variable. For example, $$y=3x+2$$ describes a function. The dependent variable appears by itself on the left hand side of equal sign.

Let us practice assigning a function using the second method described above by revisiting the first example again:

Imagine, as a physicist, you were asked to describe the velocity as a function of height. Here is what may be best described (using energy equations): The above information allows us to approximate the ball's velocity as a function of height:
 * At time $$t=0$$, the position of the ball is at a maximal height, $$h=H>0$$.
 * At time $$t=T$$ (the impact time), the ball is at a minimal height, $$h=0$$ (by assumption).
 * In between, the ball's velocity is changing. Assume an initial horizontal and vertical velocity of $$v_{0x}=0$$ and $$v_{0y}=0$$, respectively (this is true because we dropped the ball). The horizontal velocity does not change (assuming no air resistance), but the vertical velocity decreases. The final vertical velocity therefore is $$v_{y}<0$$. As such, we need to only look at the vertical velocity.
 * $$\mathbf{v}(h)=-\sqrt{2gh}$$, where $$g=9.81\frac{\text{m}}{\text{s}^{2}}$$.

The above equation is an example of a special type of function called a composite function. This function will be explained in much more detail later. For now, an intuition is all that is needed.

Hopefully, an intuition has begun forming inside the mind of the student. Let us see how to evaluate functions at certain inputs now.

If we write $$f(x)=3x+2$$, then we know that Based on the above bullet points, the way to evaluate a function at a certain point is
 * $$f$$ is a function of $$x$$.
 * To evaluate the function at a certain number, simply substitute the $$x$$ with that number.
 * Replacing $$x$$ with that number in the right side of the function will produce the function's output for that certain input.
 * In English, the definition of $$f$$ is interpreted, "Given a number, $$f$$ will return two more than thrice the input."
 * $$\begin{align}

f(3)&=3\cdot(3)+2\\ &=9+2\\ &=11 \end{align}$$ Therefore, the value of $$f(3)$$ is
 * $$f(3)=11$$. The value of $$f$$ at 3 is 11.

Note that $$f(3)$$ means the value of the dependent variable when $$x$$ (the independent variable) takes on the value of 3. So we see that the number 11 is the output of the function when we give the number 3 as the input. People often summarize the work above by writing "the value of $$f$$ at three is eleven", or simply "$$f$$ of three equals eleven".

Let us return to the function we derived in Example 1.1(c). With the function $$\mathbf{v}(h)=-\sqrt{2gh}$$, where $$g=9.81\frac{\text{m}}{\text{s}^{2}}$$, we know the following is true: When working with functions that is founded in real-life applications, it is important to also keep in mind units. Since SI units are used, and the gravitation constant $$g$$ is in meters per second-squared, the height will be in meters. We want to know what the velocity is if the ball is halfway between the bridge and the ground, $$h=\frac{H}{2}$$. Assume $$H=9.0\text{ m}$$. Let us begin evaluating the function:
 * Velocity $$\mathbf{v}$$ is a function of height, $$h$$.
 * In English, the definition of $$\mathbf{v}$$ is interpreted, "Given a height above the ground, $$\mathbf{v}$$ will return the velocity of the ball based on the square root of the product of twice the gravitational constant and the height."
 * $$\begin{align}

\mathbf{v}\left(\frac{9}{2}\right)&=-\sqrt{2g\left(\frac{9.0}{2}\right)}\\ &=-\sqrt{g\cdot9.0}\\ &=-3.0\sqrt{9.81}\approx -9.4\frac{\text{m}}{\text{s}} \end{align}$$ Therefore, the value of $$\mathbf{v}(4.5)$$ is
 * $$\mathbf{v}(4.5)\approx -9.4\frac{\text{m}}{\text{s}}$$. The value of $$\mathbf{v}$$ at $$4.5$$ is $$-9.4\frac{\text{m}}{\text{s}}$$. Quite the large increase in speed from $$0$$ meters per second!

A Note on Notation
Functions are used so much that there is a special notation for them. The notation is somewhat ambiguous, so familiarity with it is important in order to understand the intention of an equation or formula.

Though there are no strict rules for naming a function, it is standard practice to use the letters $$f$$, $$g$$ , and $$h$$ to denote functions, and the variable $$x$$ to denote an independent variable. $$y$$ is used for both dependent and independent variables.

When discussing or working with a function $$f$$, it's important to know not only the function, but also its independent variable $$x$$. Thus, when referring to a function $$f$$, you usually do not write $$f$$, but instead $$f(x)$$. The function is now referred to as "$$f$$ of $$x$$". The name of the function is adjacent to the independent variable (in parentheses). This is useful for indicating the value of the function at a particular value of the independent variable. For instance, if
 * $$f(x)=7x+1$$,

and if we want to use the value of $$f$$ for $$x$$ when $$x$$ is equal to $$2$$, then we would substitute $$2$$ for $$x$$ on both sides of the definition above and write
 * $$f(2)=7(2)+1=14+1=15$$

This notation is more informative than leaving off the independent variable and writing simply $$f$$, but can be ambiguous since the parentheses next to $$f$$ can be misinterpreted as multiplication, $$2f$$. To make sure no person is confused by notation accidentally, follow this procedure: This procedure can change if the student is doing a multiple choice exam since communication is not important in that context.
 * 1) Define the function $$f$$ by equating it to some expression.
 * 2) Give a sentence like the following: "At $$x=c$$, the function $$f$$ is..."
 * 3) Evaluate the function.

Formalizing the Intuition
As of now, the definition below should not make too much sense. Read the definition so that you may see where the we gain the understanding of the mapping.

For now, analyze the definition. Take notice at the implication of an element in the range being found through the correspondence of the element mapping from the domain. An example of how is given below.

In mathematics, it is important to notice any repetition. If something seems to repeat, keep a note of that in the back of your mind somewhere.

Here, notice that $$f(x)=5x+\frac{5x}{2}$$ and $$f(x)=225\frac{1}{2}$$. Because $$f(x)$$ is equal to two different things, it must be the case that the other side of the equal sign to $$f(x)$$ is equal to the other. This property is known as the transitive property (always remember the Properties of Real Numbers):
 * $$225\frac{1}{2}=5x+\frac{5x}{2}$$

Next, simplify — make your life easier rather than harder. In this instance, since $$5x+\frac{5x}{2}$$ has $$x$$ as a like-term, and the two terms are fractions added to the other, put it over a common denominator and simplify. Similar, since $$225\frac{1}{2}$$ is a mixed fraction, $$225\frac{1}{2}=225+\frac{1}{2}$$.
 * $$225\frac{1}{2}=5x+\frac{5x}{2}$$
 * $$\Rightarrow\frac{225}{1}+\frac{1}{2}=\frac{5x}{1}+\frac{5x}{2}$$
 * $$\Rightarrow\frac{450}{2}+\frac{1}{2}=\frac{10x}{2}+\frac{5x}{2}$$
 * $$\Rightarrow\frac{451}{2}=\frac{15x}{2}$$

Multiply both sides by the reciprocal of the coefficient of $$x$$, $$\frac{2}{15}$$ from both sides by multiplying by it.
 * $$\frac{2}{15}\cdot\frac{451}{2}=x$$
 * $$\frac{451}{15}=x$$ or $$x=\frac{451}{15}$$.

The value of $$x$$ that makes $$f(x)=225\frac{1}{2}$$ is $$x=\frac{451}{15}$$.$$\blacksquare$$.

Classically, the element "picked" from the domain is pictured as something that is fed into the function (the input) and the corresponding element in the range is pictured as the output. Notice the specificity of the language herein: an input is selected from the domain, meaning the domain is the set of all inputs; an output results from that specific input, meaning the range is the set of all possible outputs.

Since we "pick" the element in the domain whose corresponding element in the range we want to find, we have control over what element we pick and hence this element is also known as the "independent variable". The element in the range is beyond our control and is "mapped to" by the function. This element is hence also known as the "dependent variable", for it depends on which independent variable we pick. Since it is an element, the input is also known as the independent variable. Similar, the output is also known as the dependent variable.

The intuition of functions is better to grasp at first (for most students). However, the importance by which the formal definition of functions are to the foundations of algebra as we know it means that the formal definition should be viewed in high regards. Nevertheless, this does not mean that an intuition is unnecessary or even detrimental. Rather, students should be able to understand both viewpoints, and be able to relate them. As such, we argue that students should hold on to both viewpoints.

To recap, a function $$f$$ is a mapping of some element $$x\in A$$, called the domain, to exactly one element $$y\in B$$, called the range, such that $$f:A\to B$$. The image below should help explain the modern definition of a function:

The Foundations of Functions: The Mapping, the Cartesian Cross Product, and Ordered Pairs
Now that we understand the set, we will begin understanding the fundamental property of the function (the mapping). However, how do elements "map" to another set? It would be when the combination is "tied" to another element. Defining "tied" would be tricky without the help of sets. However, the set nicely defines tying, and it is through ordered pairs.

The logic in this is that the sets contained within are an element that is dependent on the order of the written pairs. Because $$\{a,b\}$$ uses both elements, the set gives the second coordinate based on the order of written pairs. However, this definition does not hold for $$b=a$$, since it evaluates to give $$(a,a)=\left\{a\right\}$$, which does not give an accurate reading of the second coordinate. However, this definition is good enough for the purposes of this textbook. Plus, the knowledge described herein is typically not taught in a College Algebra course.

The nature of the Cartesian Cross Product is hopefully self-evident. When two sets are combined as such, the ordered pair results. This is very close to the definition of the function. After all, the subset of this product is the function (for the most part).

All the above definition is saying is that given the cartesian cross product of the sets, called the domain and range, there exists a relation of the ordered pair $$(x,y)$$ that relates the domain to the range. For this book, the first notation ($$f:A\to B$$) is preferred.

Finding New Properties of Functions Using Sets
From the definitions above, new questions now arise. Here are the three main ones: can a function be (1) one-to-one? (2) many-to-one? (3) one-to-many? Consider each case. The modern definition describes a function sufficiently such that it helps us determine whether some new type of "function" is indeed one. Now that each case is defined above, you can now prove whether functions are one of these function cases. Here is an example problem: Notice that the only changing element in the function $$f$$ is $$x$$. To prove a function is one-to-one by applying the definition may be impossible because although two random elements of domain set $$A$$ may not be many-to-one, there may be some elements $$\left( a_{1},a_{2},\ldots a_{n} \right)\in A$$ that may make the function many-to-one. To account for this possibility, we must prove that it is impossible to have some result like that.
 * 1) A function is considered one-to-one if an element $$a\in A$$ from domain $$A$$ of function $$f$$, leads to exactly one element $$b\in B$$ from range $$B$$ of the function. By definition, since only one element $$b$$ is mapped by function $$f$$ from some element $$a$$, $$f:A\to B$$ implies that there exists only one element $$b$$ from the mapping. Therefore, there exists a one-to-one function because it complies with the definition of a function. This definition is similar to Figure 1.
 * 2) A function is considered many-to-one if some elements $$a_{1},a_{2},\ldots a_{n}\in A$$ from domain $$A$$ of function $$f$$ maps to exactly one element $$b\in B$$ from range $$B$$ of the function. Since some elements $$\left( a_{1},a_{2},\ldots a_{n} \right)\in A$$ must map onto exactly one element $$b\in B$$, $$f:A\to B$$ must be compliant with the definition of a function. Therefore, there exists a many-to-one function.
 * 3) A function is considered one-to-many if exactly one element $$a\in A$$ from domain $$A$$ of function $$f$$ maps to some elements $$\left( b_{1},b_{2},\ldots b_{n} \right)\in B$$ from range $$B$$ of the function. If some element $$a$$ maps onto many distinct elements $$b$$, then $$f:A\to B$$ is non-functional since there exists many distinct elements $$b$$. Given many-to-one is non-compliant to the definition of a function, there exists no function that is one-to-many.

Assume there exists two distinct elements $$x_{1}$$ and $$x_{2}$$ that will result in $$f\left( x_{1} \right) =f\left( x_{2} \right)$$. This would make the function many-to-one. In consequence, $$ax_{1}+b=ax_{2}+b$$ Subtract $$b$$ from both sides of the equation.
 * $$\Rightarrow ax_{1}=ax_{2}$$

Subtract $$ax_{2}$$ from both sides of the equation.
 * $$\Rightarrow ax_{1}-ax_{2}=0$$

Factor $$a$$ from both terms to the left of the equation.
 * $$\Rightarrow a\left( x_{1}-x_{2} \right) =0$$

Multiply $$\frac{1}{a}$$ to both sides of the equation.
 * $$\Rightarrow \left( x_{1}-x_{2} \right) =0$$

Add $$x_{2}$$ to both sides of the equation.
 * $$\Rightarrow x_{1}=x_{2}$$

Notice that $$x_{1}=x_{2}$$. However, this is impossible because $$x_{1}$$ and $$x_{2}$$ are distinct. Ergo, $$f\left( x_{1} \right)\ne f\left( x_{2} \right)$$. No two distinct inputs can give the same output. Therefore, the function must be one-to-one. There are a few more important ideas to learn from the modern definition of the function, and it comes from knowing the difference between domain, range, and codomain. We already discussed some of these, yet knowing about sets adds a new definition for each of the following ideas. Therefore, let us discuss these based on these new ideas. The below definitions are a little confusing. The best way to interpret these is to draw an image. To the right of these definitions is the image that corresponds to it (including a formal definition of the corresponding definitions).
 * The domain is defined to be a set $$A$$ with all elements $$a\in A$$ mapping to at least one unique $$b\in B$$.
 * The set of elements in $$B=R\cup\{r\}$$ and $$R=\{b\}$$ implies $$R$$ is the range of the function $$f$$ in the cartesian cross product, whereby the set of all elements $$a\in A$$ maps to at least one unique element $$b\in B$$. That is, the range is the set of all elements that was mapped by some $$a\in A$$ to one corresponding $$b\in R$$.
 * The codomain is the set $$B$$, where it is not necessarily the case that all elements $$b\in B$$ was mapped by some $$a\in A$$. That is, the set of all elements found in $$B$$ is the codomain.

The abstract concepts can also be made less confusing by using a function that can put these concepts into more concrete terms. Assume there is a function $$f$$ whereby $$x\ne2$$. Let this function be $$f(x)=2x-1$$ where $$y=f(x)$$. Let us write down what the domain, range, and codomain is for this particular function:
 * Domain: $$x\in(-\infty,2)\cup(2,\infty)$$ or $$\left\{x|x\in\mathbb{R}\wedge x\ne2\right\}$$ or simply $$x\ne2$$. In this instance, the domain is the set of all elements of $$A$$ except $$x=2$$, since this one cannot be mapped to some element in $$B$$.
 * Range: $$y\in(-\infty,3)\cup(3,\infty)$$ or $$\left\{y|y\in\mathbb{R}\wedge y\ne f(2)\right\}$$ or simply $$y\ne f(2)$$. In this instance, the range is the set of all elements of $$B$$ except $$y=f(2)$$, since this one cannot be mapped by some element in $$A$$.
 * Codomain: $$y\in(-\infty,\infty)$$ or $$\left\{y|y\in\mathbb{R}\right\}$$ or $$y\in\mathbb{R}$$. This includes the one element that we were not allowed to map.

There is one more final aspect that needs to be defined. We already have a good idea of what makes a mapping a function (e.g. it cannot be one-to-many). However, three more definitions that you will often hear will be necessary to talk about: injective, surjective, bijective. Again, the above definitions are often very confusing. Again, another image is provided to the right of the bullet points. Along with that, another example is also provided. Let us analyze the function $$g(x)=ax^{2}$$. Notice that the only changing element in the function $$g$$ is $$x$$. Let us check to see the conditions of this function.
 * A function is injective if it is one-to-one. That is, for $$a_1\in A$$ and $$a_2\in A$$, if $$f(a_{1})=f(a_{2})$$, then $$a_{1}=a_{2}$$. Otherwise, it cannot be one-to-one. The same definition from before applies for one-to-one (realize that the definition of injective and one-to-one are the same).
 * A function is surjective if it is "onto." That is, the mapping $$f:A\to B$$ has $$B$$ as the range of the function, where the codomain and the range of the function are the same.
 * A function is bijective if it is both surjective and injective.

Is it injective? Let $$g(x)=y$$, and solve for $$x$$. First, divide by $$a$$.
 * $$y=ax^{2}$$
 * $$\Rightarrow \frac{y}{a}=x^{2}$$

Then take the square root of $$x^2$$. By definition, $$\sqrt{x^{2}}=\left\vert x\right\vert=\pm x$$, so
 * $$\Rightarrow\sqrt{\frac{y}{a}}=\pm x$$

Notice, however, what we learned from the above manipulation. As a result of solving for $$x$$, we found that there are two inputs, $$\pm x$$, that give the same output,$$\sqrt{\frac{y}{a}}$$. This means that for some individual $$x$$ that gives $$y$$, there are two different inputs that result in the same value. Because $$f(x_{1})=f(x_{2})$$ when $$x_{1}\ne x_{2}$$, this is by definition non-injective.

Is it surjective? As a natural consequence of what we learned about inputs, let us determine the range of the function. After all, the only way to determine if something is surjective is to see if the range applies to all real numbers. A good way to determine this is by finding a pattern involving our domains. Let us say we input a negative number for the domain: $$f(-x)=a(-x)^{2}=a\cdot(-x)\cdot(-x)=ax^2$$. This seemingly trivial exercise tells us that negative numbers give us non-negative numbers for our range. This is huge information! For $$x\in\mathbb{R}$$, the function always results $$y>0$$ for our range. For the set $$B$$, we have elements in that set that have no mappings from the set $$A$$. As such, $$y\le0$$ is the codomain of set $$B$$. Therefore, this function is non-surjective! Functions are an important foundation of mathematics. This modern interpretation is a result of the hard work of the mathematicians of history. It was not until recently that the definition of the relation was introduced by René Descartes in Geometry (1637). Nearly a century later, the standard notation ($$f(x)=y$$) was first introduced by Leonhard Euler in Introductio in Analysin Infinitorum and Institutiones Calculi Differentialis. The term function was also an innovation during Euler's time as well, being introduced Gottfried Wilhelm Leibniz in a 1673 letter "to describe a quantity related to points of a curve, such as a coordinate or curve's slope." Finally, the modern definition of the function being the relation among sets was first introduced in 1908 by Godfrey Harold Hardy where there is a relation between two variables $$x$$ and $$y$$ such that "to some values of $$x$$ at any rate correspond values of $$y$$." For the person that wants to learn more about the history of the function, this page has been provided for you.

Summary of the Set Definitions of Functions
This section is perhaps the hardest to understand. A summary is provided before the end of the chapter to help students further their understanding. The summary only uses jargon terms. For the student that was able to understand and translate the jargon, they are ready to move on to the "Check your understanding." It is in the student's best interest to understand this section because the terms will come back again so that students may fully appreciate the intuition behind composite functions and inverse functions, which we will define in due time. Plus, these definitions are sometimes necessary for proofs. Having a good understanding of these basic foundations of functions will be helpful for the student throughout math, even for students who are not math majors.
 * A cartesian cross product is the operation $$A\times B=\{(x,y)|x\in A,\,y\in B\}$$, where $$A$$ and $$B$$ are two distinct sets.
 * A mapping is a relation denoted by $$f:A\to B$$, where $$A$$ and $$B$$ are two distinct sets, such that the cartesian cross product $$A\times B$$ results in the ordered pair $$(x,y)$$ for any given $$x\in A$$ to some unique $$y\in B$$.
 * A function is a mapping of the set of all inputs, the domain, $$A$$, to the set of all corresponding outputs, the range, $$B$$ such that for any $$x\in A$$, the cross product is true for one and only one $$y\in B$$.
 * The element $$a\in A$$ is an input. The entire set $$A$$ is the domain (since it comprises all inputs). For any $$r\in B$$ but $$r\notin R$$ and $$b\in R$$ gives $$R=\{b\}$$. $$R\subseteq B$$ implies $$R$$ is the range if the cartesian cross product $$A\times B$$ results in $$(a,b)$$. The set $$B=R\cup\{r\}$$ is the codomain.
 * Let $$f: A\to B$$. A function is injective when for all $$a_1\in A$$ and $$a_2\in A$$, if $$f(a_{1})=f(a_{2})$$, then $$a_{1}=a_{2}$$. Symbolically, $$\forall a_{1},a_{2}\in A\left(f\left(a_{1}\right) = f\left(a_{2}\right)\Rightarrow a_{1} = a_{2}\right)$$.
 * A function is surjective if the mapping $$f: A\to B$$ has $$B$$ as the range and codomain of the function. Put another way, if $$f: A\to B$$, then $$f$$ is said to be surjective if $$\forall y\in B \; \exists x \in A\left(f(x) = y\right)$$.
 * A function is bijective if it is both injective and surjective.

Remarks
The following arise as a direct consequence of the definition of functions:
 * 1) By definition, for each "input" a function returns only one "output", corresponding to that input. While the same output may correspond to more than one input, one input cannot correspond to more than one output. This is expressed graphically as the vertical line test: a line drawn parallel to the axis of the dependent variable (normally vertical) will intersect the graph of a function only once. However, a line drawn parallel to the axis of the independent variable (normally horizontal) may intersect the graph of a function as many times as it likes. Equivalently, this has an algebraic (or formula-based) interpretation. We can always say if $$a=b$$, then $$f(a)=f(b)$$ , but if we only know that $$f(a)=f(b)$$ then we can't be sure that $$a=b$$.
 * 2) Each function has a set of values, the function's domain, which it can accept as input. Perhaps this set is all positive real numbers; perhaps it is the set {pork, mutton, beef}. This set must be implicitly/explicitly defined in the definition of the function. You cannot feed the function an element that isn't in the domain, as the function is not defined for that input element.
 * 3) Each function has a set of values, the function's range, which it can output. This may be the set of real numbers. It may be the set of positive integers or even the set {0,1}. This set, too, must be implicitly/explicitly defined in the definition of the function.

The vertical line test
The vertical line test, mentioned in the preceding paragraph, is a systematic test to find out if an equation involving $$x$$ and $$y$$ can serve as a function (with $$x$$ the independent variable and $$y$$ the dependent variable). Simply graph the equation and draw a vertical line through each point of the $$x$$-axis. If any vertical line ever touches the graph at more than one point, then the equation is not a function; if the line always touches at most one point of the graph, then the equation is a function.

(There are a lot of useful curves, like circles, that aren't functions (see picture). Some people call these graphs with multiple intercepts, like our circle, "multi-valued functions"; they would refer to our "functions" as "single-valued functions".)

title: CLEP College Algebra/Functions


text:
Planet Earth/8d. How to Think Critically About Earth's Future

The Earth is an isolated planet that contains all that you love and know. As change comes in the form of events in the near and distant future, the Earth will undoubtedly transform to accommodate these changes. To adapt, you will need to study the scientific methods to bring about a better place for this unknowable future. Science is not a doctrine to believe blindly, but a process to investigate and propose solutions to problems as they arise. Throughout this course, you have been introduced to the wonderous planet that you call your home, its gas atmosphere, liquid oceans, rough terrestrial terrain and deep interior of rock and heat. You’ve learned a little about the lifeforms, an oddity that makes the planet so unique in our solar system, as well as the rise of intelligent creatures such as yourself, a species that has come to dominate the planet. The Earth’s story is mixed with the individual hopes and dreams of various people who have investigate the wonderous planet they live upon, to understand the reality of existence through observation and ardent collection of data. Theories and ideas supported by experimentation and testing. What you take from this course will guide you in further explorations of these topics, beyond what a simple online class is able to convey. This final chapter, this final module, will leave you with a sense of direction of where to go and how to conducted your life to more critically think about the world around you.

Don’t Believe Everything that is Told to You
In the modern world, the goal of any propogandist or advertiser is to gain your attention. The rise of conspiracy theories, misconceptions, fallacies of thought rise out of your consumption of the media that is feed to you. Images of outrage, violence, hatred, death and despair carry a heavy emotional impact that can be a powerful motivating force, used to elicit reaction and attention from you.

In the modern world, it can be difficult to determine what reality is, and what is propaganda or false ideas or mistaken concepts. Every idea cannot be tested by an individual investigator. You may not have access to the equipment, materials, animals, test subjects or data necessary to conduct the study yourself. You instead must rely on the experiments of others, on the data collection provided by those scientists who have done the experiments. Sometimes these are wrong, and hence re-testing and the verification of those experiments are necessary by other scientists. Science changes with each re-examination, and often requires multiple labs and institutions on an international scale of research. A single entity cannot dictate the reality of an experimental outcome, but only through re-testing and verification from many sources and unique institutions can you come to a better understanding of the world around you. This requires a global and international pursuit of knowledge, and with the free exchange of ideas.

The future will bring new technological breakthroughs in preserving the natural world, and human dominance of the Earth. Some of these technologies will bring forth new responsibilities, while others might solve the great crises that we face today. Replacing antiqued modes of transportation, air polluting sources of energy, and more sustainable solutions for a more cost effective and less destructive resource utilization of Earth’s materials, both organic and inorganic is needed. The old ways of living on Earth are unsustainable, requiring new ways to drive economic pursuits that safely protect the environment and human health. This will require better governance, and increased participation of science within policy decisions.

What can you do?
Increasing personal knowledge and educating yourself about science is the most important aspect to living a good life. Knowledge allows you to comprehend the interestingly complex world around you, and to be weary of those who purport to be all knowing or authoritarian. Division and resentment are bred from ignorance. Research topics that interest you. Learn to read scientific reports and primary scientific literature that you can access, including books and other literature. Pursue multiple perspectives and personal experiences from others. Be empathic in your learning, and remain open to new ideas and new concepts. Learn to read charts and graphs and what they mean, and how to be critical of ideas. Be cautious of journalistic sensationalism, which uses shocking news stories at the expense of accuracy to provoke interest and further readership to sell advertising. Be observant about the world around you through exploration of your corner of the Earth, and the changes that you can witness and document near your home. Participate in changes that you would like to see in your own future, and those of future generations. Vote and participate in the politic processes to change the world, and write and contribute your own perspective to others, and share your own ideas. Read as much as you can, travel and experience new cultures and places, and share your own experiences living on Earth. Set goals, either personal ways to change your own consumption of materials, but also influence others to make similar changes. Review important scientific reports, and keep informed on the topics that are important to you. Don’t rely on social media for knowledge or as an assessment of the world around you. Ignore stranger’s comments and anger that can make you to lose hope, and realize that the right path toward a brighter future is often filled with thorns of personal scorn and ridicule. Stay the course to your goals and your own pursuit of happiness.

What will your future Earth look like?

You share the same planet with every other human on the planet. You breathe the same air as everyone else. You require the same basic necessitates of life including good food, clean freshwater and sound well-built shelters. You were born here, and will die here, like every other living human on the planet. Your view of Earth is a tiny fraction of the planet’s vast existence. As one of the multitudes of people and fellow humans, your view of the future will be different and unique. It is up to you to make it better, but only if you work hard at it. Life on Earth is not set to last for an eternity, it takes a lot of care, a lot of knowledge and understand, and a lot of love to ensure you and everyone on the planet is happy and healthy, enjoying that tiny moment of their own time on Earth. Focus on the little things you can do to make the Earth better. Pick up some litter while hiking, help someone that is in trouble, show kindness and understanding even to people with multiple views and opinions, and work toward solutions to problems. Dispel hatred with kindness. An enormous weight of responsibility comes from knowledge, because you carry the knowledge in knowing that the atmosphere, oceans and water, life and the physical resources of Earth are rapidly changing, and being altered at an alarming rate. You understand now that there is a colossal responsibility in the educating others. This course will stay with you for the rest of your life, this knowledge will keep you pressing forward to learn more, and with that comes the responsibility to educate others with this gainful knowledge about your and everyone else’s planet— Earth.


text: Planet Earth/print version

title: Planet Earth/print version


text:
Chess Opening Theory/1. e4/1...Nc6/2. d4/2...e6

In this position, 3. Nf3 is the most common move. The pawn structure will soon resemble the Advance Variation of the French Defence.


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SPARQL/Wikimedia Commons Query Service

Wikimedia Commons images use structured data too, see Structured Data on Commons (SDoC). With Wikimedia Commons Query Service (WCQS) the data can be queried. This is available per 1/2/2022 at https://commons-query.wikimedia.org/ It was previously available in beta phase at https://wcqs-beta.wmflabs.org/.

Find below an example of Depictions of Douglas Adams shown as image grid.

Mind: use  where sdc =Structured Data on Commons, the default is   for Wikidata.

See more examples on WCQS itself.

The query below shows all properties of an image:

This reveals some hidden statements like: date Modified / width / height / contentSize (bytes). The query below gives an example how to use it.

This example with combination of SERVICE - mwapi shows Depicts statements with Dutch labels, of files in one Commons category

title: SPARQL/Wikimedia Commons Query Service


text:
Talk:AppleScript Programming/Shell Programming

Trying to run or save

results in the following error: Syntax Error

Expected end of line, etc. but found unknown token.

And at the moment, I don't know enough to fix it (that's one of the reasons I'm going though this wikibook).

--166.70.72.169 (discuss) 17:21, 24 July 2020 (UTC)