What is … the secret of the zeta function?

This page hosts information on Hannah Sjöberg's talk "What is … the Euler characteristic of a polytope?" at the "What is …?" seminar. This talk will help you better understand the talk by Raman Sanyal.

Where & When

• Friday, November 9, 2018, 1.00pm @ room Netwton, 2nd floor at Urania

Abstract

• The Euler characteristic of a non-empty (solid) polytope P is the

alternating sum of the number of non-empty i-dimensional faces of P. The Euler-Poincaré formula asserts that this alternating sum is equal to 1. In this talk we discuss how the Euler characteristic can be constructed as a valuation. The construction has nice applications: we will see that it gives us simple proofs of the Euler-Poincaré formula and of a theorem on the number of regions in a hyperplane arrangement.