Graph Density Inequalities, Sums of Squares and Tropicalization

Annie Raymond (University of Massachusetts)

19-Apr-2021, 14:00-15:00 (3 years ago)

Abstract: Establishing inequalities among graph densities is a central pursuit in extremal graph theory. One way to certify the nonnegativity of a graph density expression is to write it as a sum of squares or as a rational sum of squares. In this talk, we will explore how one does so and we will then identify simple conditions under which a graph density expression cannot be a sum of squares or a rational sum of squares. Tropicalization will play a key role for the latter, and will turn out to be an interesting object in itself. This is joint work with Greg Blekherman, Mohit Singh, and Rekha Thomas.

combinatoricsprobability

Audience: researchers in the topic


Extremal and probabilistic combinatorics webinar

Series comments: We've added a password: concatenate the 6 first prime numbers (hence obtaining an 8-digit password).

Organizers: Jan Hladky*, Diana Piguet, Jan Volec*, Liana Yepremyan
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