2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/116624We study conditional expectations generated by an abelian $ C^* $-subalgebra in the centralizer of a positive functional. We formulate and prove Jensen's inequality for functions of several variables with respect to this type of conditional expectations, and we obtain as a corollary Jensen's inequality for expectation values.Operator Algebras47A63; 26A51text