Centers of semigroup rings and conjugacy classes.
Combinatoric of syzygies for semigroup algebras.
We describe how the graded minimal resolution of certain semigroup algebras is related to the combinatorics of some simplicial complexes. We obtain characterizations of the Cohen-Macaulay and Gorenstein conditions. The Cohen-Macaulay type is computed from combinatorics. As an application, we compute explicitly the graded minimal resolution of monomial both affine and simplicial projective surfaces.
Commutative semigroup rings which are principal ideal rings
Construction of set theoretic complete intersections via semigroup gluing.
Correction to my paper "On a type of matrix semigroup algebras" .
Counting with groups and rings.