One of the highlights in the Robertson-Seymour theory on graph minors is the finiteness (for each fixed surface S) of the set of the minimal forbidden minors for S. Theorem 7.0.1 (Robertson and ...
August 15, 2017 (8/15/17) was Pythagorean Theorem Day (see I missed Pythagorean Theorem Day). I was not even aware that there was such a day until this year, but it brought to my attention some really ...