/ Giorgio Genovesi: Characterizing Regular Countable Second Countable Spaces in Second Order Arithmetic

Giorgio Genovesi: Characterizing Regular Countable Second Countable Spaces in Second Order Arithmetic

20th March 2025
2:00 pm - 3:00 pm

Abstract: Regular countable second countable (CSC) spaces admit rather nice characterizations and can easily be formalized in second order arithmetic. It is natural to ask what set existence axioms are needed to ensure regular CSC spaces remain nice. It turns out many theorems which characterize regular CSC are equivalent to one of the big five subsystems of second order arithmetic.