Physics - Math Colloquium
Speaker: Prof. Dr. Cihan Saçlıoğlu, Sabancı University, İstanbul
Title: The wild world of 4-manifolds
Date/Time: Aprl. 25 Wednesday at 10:40
Place: SUNUM Building G-111
Tea, coffee and cookies @ 10:15 in SUNUM Hall.
Four-manifolds first came into physics through Einstein's General theory of
relativity, which relates large-scale gravitational phenomena to the
metric-based Riemannian curvature of space-time. In the mathematical study
of manifolds, on the other hand, a fundamental problem is the classification
of manifolds in all dimensions through their topological and other invariants.
In 1956, Milnor exhibited 28 spheres in 7 dimensions which were topologically
indistinguishable, but differentiably inequivalent. This surprising
proliferation of so-called "exotic" or "fake" versions of the same topological
manifold starts at dimension 4, which is also where the most bizarre varieties
are found. For example, there are uncountably many "fake" R's, a phenomenon 4
not encountered in any other dimension. We'll give an overview of the field
and offer a speculation about its possible relevance to physics.
Contact: İnanç Adagideli, email@example.com
and/or Cem Çelebi, firstname.lastname@example.org