You are cordially invited to the Topology Seminar organized by the Department of Mathematics.
Speaker: Özgün Ünlü (Bilkent)
“Counterexamples to the Oozing Conjecture ”
Abstract: I will begin with a brief introduction to surgery theory and assembly maps. I will then discuss joint work with Ian Hambleton, in which we construct counterexamples to the Oozing conjecture. The Oozing Conjecture predicts that Arf-type surgery obstructions do not produce new classes under sufficiently high-codimension products. Examples of Morgan–Pardon and Cappell–Shaneson exhibit non-triviality in codimensions 2 and 3, respectively. We give a new example in codimension 4.
Date: April 27, Monday, 2026
Time: 15:30
Place: SA141