國立清華大學 數學系

參考連結
https://sites.google.com/view/sgsnthu/home

Abstract:
In this talk, we will consider Brown functors of directed graphs --- that is, contravariant functors from the homotopy category of finite directed graphs to the category of abelian groups, satisfying the triviality axiom, the additivity axiom, and the Mayer-Vietoris axiom. Our main theorem states that such a functor is representable. In addition, I will show that the first path cohomology of directed graphs provides a nontrivial example of a Brown functor. This talk is based on joint work with Zachary McGuirk, Dang Khoa Nguyen, and Byungdo Park.