src/HOL/ex/Erdoes_Szekeres.thy
2016-04-25 wenzelm 2016-04-25 eliminated old 'def'; tuned comments;
2016-02-23 nipkow 2016-02-23 more canonical names
2015-10-06 wenzelm 2015-10-06 isabelle update_cartouches;
2015-06-12 bulwahn 2015-06-12 add examples from Freek's top 100 theorems (thms 30, 73, 77)