Universal Algebra seminar

Alexander Wires, Department of Pure Mathematics, University of Waterloo

“Dichotomy for Finite tournament of Mixed-type I”

Since irreflexive digraphs often pp-define partially reflexive digraphs, we can show they yield NP-complete CSP templates by understanding certain mixed-type cases. A tournament of mixed-type is a digraph in which distinct vertices have exactly one oriented edge between them, and loops are not prohibited. We classify tournaments of mixed-type closed under a Taylor operation, and show their polymorphism algebras generate congruence meet-semidistributive varieties. In this first talk, we start the proof of this result.