Grigory Ivanov: Geometric representation of 1 / s -concave functions and dualityIvanov Grigory
Abstract: Hedetniemi conjectured in 1966 that for all graphs . This conjecture received a lot of attention in the past half century and was eventually refuted by Shitov in 2019. The Poljak-Rödl function is defined as . It is obvious that for all , and Hedetniemi’s conjecture is equivalent to say that for all integer . Now we know that for large . However, we do not know how small can be. In this talk, we will present new counterexamples to Hedetniemi's conjecture. We show that and survey some other work related to Hedetniemi’s conjecture.