2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/225690Let A be a finitely generated commutative algebra over a field K with a presentation A=K < X_{1}, ..., X_{n} | R >, where R is a set of monomial relations in the generators X_{1}, ..., X_{n}. So A = K[S], the semigroup algebra of the monoid S=< X_{1}, ..., X_{n} | R >. We characterize, purely in terms of the defining relations, when A is an integrally closed domain, provided R contains at most two relations. Also the class group of such algebras A is calculated.17 pages, 0 figures, to appear in International Journal of Algebra and ComputationRings and AlgebrasCommutative Algebra16S36, 13B22text