Transformation Groups Seminar

Speaker: Kumar Shukla (Western)

"Piecewise polynomial ring as equivariant cohomology of toric varieties"

Time: 09:30

Room: MC 106

We will define piecewise polynomial ring over a fan and discuss some properties of this ring. Then we will show that the equivariant cohomology of a toric variety over a fan Σ (with vanishing odd cohomology) is given by piecewise polynomials over Σ.

Colloquium

Speaker: Cihan Okay (Bilkent University)

"Simplicial distributions and contextuality"

Time: 12:30

Room: MC 108

In modern homotopy theory, spaces are represented by combinatorial models called simplicial sets. Their elegant formulation gives them great expressive power to capture spaces up to homotopy. Simplicial distributions are basic mathematical objects that mix simplicial sets with probabilities. That is, they model probability distributions on spaces. In my talk, I will show how simplicial distributions provide a framework for studying a central quantum feature associated with probabilities, known as contextuality. A typical measurement scenario consists of a set of measurements and outcomes, whereas simplicial distributions can be defined for spaces of measurements and outcomes. Our approach unifies and goes beyond two earlier approaches: the sheaf-theoretic (Abramsky-Brandenburger) and group cohomological (Okay-Roberts-Bartlett-Raussendorf).