2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/101271This paper is devoted to the study of various maximal ergodic theorems in noncommutative $L_p$-spaces. In particular, we prove the noncommutative analogue of the classical Dunford-Schwartz maximal ergodic inequality for positive contractions on $L_p$ and the analogue of Stein's maximal inequality for symmetric positive contractions. We also obtain the corresponding individual ergodic theorems. We apply these results to a family of natural examples which frequently appear in theory of von Neumann algebras and in quantum probability.This is a revised version with minor modifications. To appear in J. Amer. Math. SocOperator AlgebrasDynamical SystemsFunctional AnalysisPrimary 46L53, 46L55; Secondary 46L50, 37A99text