Door is open and coffee served from 13.30. The seminar will start at 14.00.
Abstract
The "Hauptvermutung" was one of the famous conjectures from the beginning
of topology, and concerns the problem of uniqueness of triangulations. John Milnor
(Abel prize 2011) in 1961 showed that it fails for arbitrary complexes, but except for
low dimensions the manifold version remained open. But in 1965 Dennis Sullivan,
in his doctoral thesis, proved the conjecture for a large class of manifolds. This was
a real tour de force, where he introduced new methods and made striking calculations
which have had lasting impact both in manifold topology and homotopy theory.
I will discuss the conjecture and some of its history and then try to give some non-
technical explanations of some of the ideas that Sullivan used and developed
along the way.
Welcome.