second order arithmetic talk

GLLC 14½ talk: Topological regularities in second order arithmetic

I am very happy that I was invited at the “Games in Logic, Language and Computation 14½" meeting at the ILLC in Amsterdam (where I finished my masters) to give this talk. The talk is based on work by Peter Koepke and Michael Möllerfeld. It shows that ZFC is equiconsistent with full second order arithmetic (SOA) plus all sets of reals are Lebesgue measurable, have the Baire property and the perfect set property. I helped finish off the forcing side (which admittedly is a bit disappointingly easy). These are the slides.