Affine semigroups and Cohen-Macaulay rings generated by monomials
Affine semigroups and Cohen-Macaulay rings generated by monomials
We give a criterion for an arbitrary ring generated by monomials to be Cohen-Macaulay in terms of certain numerical and topological properties of the additive semigroup generated by the exponents of the monomials. As a consequence, the Cohen-Macaulayness of such a ring is dependent upon the characteristic of the ground …