Using Brouwer's fixed point theorem

Abstract

Brouwer's fixed point theorem from 1911 is a basic result in topology - with a wealth of combinatorial and geometric consequences. In these lecture notes we present some of them, related to the game of HEX and to the piercing of multiple intervals. We also sketch stronger theorems, due to Oliver and others, and explain their applications to the fascinating (and still not fully solved) evasiveness problem.

46 pages, many figures. To appear in "A Journey through Discrete Mathematics. A Tribute to Jiri Matousek", edited by Martin Loebl, Jaroslav Nesetril and Robin Thomas, due to be published by Springer