# CSM

## Seminar

### Resummation of cluster (Mayer) expansions

Meeting Room 3, CMS

#### Abstract

For polymer models, suitable rearrangement (resummation, renormalization) of expansions of their partition functions is often a key step in making them useful, when evaluating their free energy or when estimating their "surface terms". Most interesting is the case, when resummation enables to estimate also sums of non-absolutely converging terms. I will show examples of polymer models (where polymers are cycles resp. walks with hard or soft repulsion) which are close to those appearing in the study of perturbations of massless gaussian models and which allow some interesting resummations, and useful bounds on their convergence