La Semicontinuidad en el Surgimiento de la Teoría de Funciones

In this article deals with the work of French mathematician Ren′e Baire and some historical aspects relevant to consider that led to the realm of theory functions as a branch formal mathematics. Will also discuss the concept of semicontinuity, which was instrumental in the development of Baire theory and is regarded as one of the most important concepts of analysis. Finally exhibit obtaining a continuous function "exotic" which is presumed, is di erentiable at best, in a nite number of points within a narrow range.