This thesis is a contribution to the research program ‘toposes as bridges’ introduced in [12], which aims at developing the unifying potential of the notion of Grothendieck topos as a means for relating different mathematical ...

The aim of this work is to explore the relationship between the manipulation of linguistic objects and the development of logical-deductive abilities, through teaching experiments in primary and secondary schools. Our ...

The service sector lies at the heart of industrialized nations and continues to serve as a major contributor to the world economy. Over the years, the service industry has given rise to an enor- mous amount of technological, ...

A conservation law is a partial di_erential equation, in which the variable is a quantity which remains constant in time, that is it cannot be created and destroyed. Thanks to the conservation laws it is possible to de_ne ...

This thesis is composed of four chapters, two of which, Chapter 3 and Chapter 4, contain original results. In Chapter 1 we recall some basic notions and establish some of the notation and terminology which will be used in ...