SMS scnews item created by Anthony Henderson at Fri 6 Jun 2008 1546
Type: Seminar
Distribution: World
Expiry: 20 Jun 2008
Calendar1: 20 Jun 2008 1205-1255
CalLoc1: Carslaw 373
CalTitle1: Algebra Seminar: Stapledon -- Weighted Ehrhart theory and orbifold cohomology
Auth: anthonyh@asti.maths.usyd.edu.au

Algebra Seminar

Weighted Ehrhart theory and orbifold cohomology

Alan Stapledon

20th June, 12:05-12:55pm, Carslaw 373


Abstract

If P is a lattice polytope, then one can define a polynomial deltaP(t), which encodes the number of lattice points in any fixed dilation of P. The polynomial deltaP(t) is a classic combinatorial invariant, called the Ehrhart delta-polynomial of P. We will present a new geometric interpretation of the coefficients of deltaP(t). That is, they are sums of dimensions of orbifold cohomology groups of a toric stack. As a combinatorial application, we will prove a weighted version of Ehrhart Reciprocity.


After the seminar we will take the speaker to lunch.

See the Algebra Seminar web page for information about other seminars in the series.

Anthony Henderson anthonyh@maths.usyd.edu.au.



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