2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/225288The relationship between the GNS representations associated to states on a quasi *-algebra, which are {\em local modifications} of each other (in a sense which we will discuss) is examined. The role of local modifications on the spatiality of the corresponding induced derivations describing the dynamics of a given quantum system with infinite degrees of freedom is discussed.Jour. Math. Anal. Appl., in pressMathematical Physicstext