FKG (and other inequalities) via (generalized) FK representation (and iterated folding)

Abstract

In this paper we prove several inequalities by means of diagrammatic expansions, a technique already used in [BG13]. This time we show that iterations of the folding of a probability leads to the proof of some in- equalities by means of a generalized random cluster representation of the iterated foldings. One of the inequalities is the well known FKG inequal- ity, which ends up being proven, quite unexpectedly, by means of the (generalized) FK representation. Although most of the results are not new, we hope that the techniques will find applications in other contexts.