Introduction

Abstract

Statistical physics has faced for long time the challenge to describe and understand large complex systems composed by a heterogeneous set of elements that interact mainly via non-local interactions. In this sense, while the study of their homogeneous counterparts with local interactions has resulted in most significative achievements (consider for example the theory of critical phenomena), heterogeneous systems have usually been the subject of much less attention, due to the intrinsic difficulty that their analytical treatment implies.