field_of_work mark goresky
A ___MASK70___ is someone who uses an extensive knowledge of ___MASK82___ in his / her work , typically to solve mathematical problems . Robert Mark Goresky ( born 1950 ) is a Canadian ___MASK70___ who invented intersection homology with Robert MacPherson . He received his Ph . D . from Brown University in 1976 . His thesis , titled Geometric Cohomology and Homology of Stratified Objects , was written under the direction of MacPherson . Many of the results in his thesis were published in 1981 by the American Mathematical Society . He has taught at the University of British Columbia in Vancouver , and Northeastern University . In 2012 he became a fellow of the American Mathematical Society . The Canadian titles debate has been ongoing since the presentation to the Canadian House of Commons of the Nickle Resolution in 1917 . This resolution marked the earliest attempt to establish a Canadian government policy requesting the sovereign not to grant knighthoods , baronetcies , and peerages to Canadians and set the precedent for later policies restricting Canadians from accepting titles from foreign countries . Dissatisfaction with the British honours system led to the gradual creation of a separate system for Canada . In ___MASK20___ , a branch of mathematics , intersection homology is an analogue of singular homology especially well - suited for the study of singular spaces , discovered by Mark Goresky and Robert MacPherson in the fall of 1974 and developed by them over the next few years . ___MASK82___ ( from Greek  " máthma ",  knowledge , study , learning ) is the study of topics such as quantity ( numbers ), structure , space , and change . There is a range of views among mathematicians and philosophers as to the exact scope and definition of ___MASK82___ . An earl is a member of the nobility . The title is Anglo - Saxon in origin , akin to the Scandinavian form jarl , and meant " chieftain ", particularly a chieftain set to rule a territory in a king ' s stead . In Scandinavia , it became obsolete in the ___MASK54___ and was replaced by duke (" hertig "/" hertug "/" hertog "). In later medieval Britain , it became the equivalent of the continental count ( in England in the earlier period , it was more akin to a duke ; in Scotland it assimilated the concept of mormaer ). However , earlier in Scandinavia , " jarl " could also mean a sovereign prince . For example , the rulers of several of the petty kingdoms of Norway had the title of " jarl " and in many cases they had no less power than their neighbours who had the title of king . Alternative names for the " Earl / Count " rank in the nobility structure are used in other countries , such as Hakushaku during the Japanese Imperial era . A mathematical problem is a problem that is amenable to being represented , analyzed , and possibly solved , with the methods of ___MASK82___ . This can be a real - world problem , such as ___MASK27___ the orbits of the planets in the solar system , or a problem of a more abstract ___MASK72___ , such as Hilbert ' s problems .< br > It can also be a problem referring to the ___MASK72___ of ___MASK82___ itself , such as Russell ' s Paradox . A knight is a person granted an honorary title of " knighthood " by a monarch or other political leader for service to the monarch or country , especially in a ___MASK61___ capacity . Historically , in Europe , knighthood was conferred upon mounted warriors . During the High Middle Ages , knighthood was considered a class of lower nobility . By the Late Middle Ages , the rank had become associated with the ideals of chivalry , a code of conduct for the perfect courtly Christian warrior . Often , a knight was a vassal who served as a fighter for a lord , with payment in the form of land holdings . The lords trusted the knights , who were skilled in battle on horseback . Since the early modern period , the title of knight is purely honorific , usually bestowed by a monarch , as in the British honours system , often for non - ___MASK61___ service to the country . The modern female equivalent in the United Kingdom is Dame . In ___MASK82___ , ___MASK20___ ( from the Greek  , " place ", and  , " study ") is concerned with the properties of space that are preserved under continuous deformations , such as stretching and bending , but not tearing or gluing . This can be studied by considering a collection of subsets , called open sets , that satisfy certain properties , turning the given set into what is known as a topological space . Important topological properties include connectedness and compactness . In algebraic ___MASK20___ , a branch of mathematics , singular homology refers to the study of a certain set of algebraic invariants of a topological space " X ", the so - called homology groups formula_1 . Intuitively spoken , singular homology counts , for each dimension " n ", the " n "- dimensional holes of a space . Singular homology is a particular example of a homology theory , which has now grown to be a rather broad collection of theories . Of the various theories , it is perhaps one of the simpler ones to understand , being built on fairly concrete constructions .