Arf Lectures 2026: Exotica in Dimension Four

Abstract: Four-dimensional spaces behave very differently than spaces of any other dimension. This ‘exotic’ behavior was unrevealed by work of Freedman and Donaldson in the early 80’s, and led to several surprising and interesting discoveries since then. In the lecture we will concentrate on exotica on ‘definite’ four-manifolds, and indicate their relevance in the ’smooth four-dimensional Poincaré conjecture’ the last open question in this circle of problems regarding the topology of spheres.

Mathematics

Audience: researchers in the topic

METU Mathematics General Seminar