In the recent decades mathematical logic has become more and more important in computer science and, in general, in system engineering. In fact, by definition, it is the wey of expressing our reasoning in terms of mathematical formalism, thus supplying it with the typical rigor and precision of mathematics. Not by chance, automatic information processing is now pervasive and we find it practically in any human activity and artefact, from embedded, safety-critical systems, to e-commerce, to social networks, etc. Such a pervasiveness and the consequent heterogeneity of the involved systems mandate much more generality in the formalism supporting the engineering activity than traditional specialized models such as, e.g., those for electric circuits and mechanical engines: mathematical logic, paired with computer applications, provides such generality.