A guide to tropical modifications
This paper surveys tropical modifications, which have already become folklore in tropical geometry. Tropical modifications are used in tropical intersection theory and in a study of singularities. They admit interpretations in various contexts such as hyperbolic geometry, Berkovich spaces, and non-standard analysis. Our main goal is to mention different points of view, to give references, and to demonstrate the abilities of tropical modifications. We assume that the reader had already met "tropical modifications" somewhere and wants to understand them better. There are novelties here: a new obstruction (Theorem 2.29) for realizability of non-transversal intersections is found and a tropical version of Weil's reciprocity law (Theorem 2.10) is proven via tropical Menelaus Theorem. A generalization of tropical momentum is given in Section 2.6.