2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/124353Let $I$ be a monomial ideal of the polynomial ring $S=K[x_1,...,x_4]$ over a field $K$. Then $S/I$ is sequentially Cohen-Macaulay if and only if $S/I$ is pretty clean. In particular, if $S/I$ is sequentially Cohen-Macaulay then $I$ is a Stanley ideal.11 pagesCommutative AlgebraPrimary 13H10 Secondary 13P10, 13C14, 13F20text