Ein optimaler Satz über offene Abbildungen.
In this paper we develop a duality theory of the closed graph theorem with weak continuity conditions, in order to obtain some permanence and maximality properties concerning the domain and range classes.
This paper is devoted to the study of semi-LpB spaces, which coincide with the semi-LB spaces defined by Valdivia when p = 1. We give new results in localization and lifting. We study the relation between the class of semi-LpB spaces and the class of webbed spaces. Finally we obtain localization theorems without any convexity assumptions.