ABOUT SOME FORMALISMS OF INTERACTION - PHASE-TRANSITION MODELS IN ECONOMICS

The aim of the present work is to scrutinise the economic use of phase transitions formalisms and to assess their relevance. The formal corr espondence between the issue of micro-macro passage when agents are in teracting and the physics problem of phase transition is first set out . The second section presents two formal tools likely to be associated with these problems and to exhibit the typical phenomena of phase tra nsition. It is then possible to highlight the key points upon which th e phase transition phenomena in these formal representations rely, and then to assess the relevance of their economic ''counterparts'' assoc iated with these crucial characteristics. A more general appraisal of these formalisms for economics is finally sketched.