2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/65196Let I be a divisorial ideal of a strongly F-regular ring R. Watanabe asked if the symbolic Rees algebra R_s(I) is Cohen-Macaulay whenever it is Noetherian. We develop the notion of multi-symbolic Rees algebras, and use this to show that R_s(I) is indeed Cohen-Macaulay whenever a certain auxiliary ring is finitely generated over R.Commutative Algebra13A30; 13A35; 13H10text