Two-color solutions of set-theoretic tetrahedron equation and their cohomologies

Abstract

All solutions of the set-theoretic constant tetrahedron equation with two colors are found, and some of their properties are analyzed. The list includes 406 solutions - we call them R-operators, - most of which are degenerate (non-bijective). Then, we calculate the 3-cohomologies for our R-operators, and discuss the applicability of our results to 3-dimensional statistical physics.