STACKING MODELS OF VESICLES AND COMPACT CLUSTERS

We investigate three simple lattice models of two dimensional vesicles . These models differ in their behavior from the universality class of partially convex polygons, which has been recently established. They do not have the tricritical scaling of those models, and furthermore d isplay a surprising feature: their (perimeter) free energy is disconti nuous with an isolated value at zero pressure. We give the full asympt otic descriptions of the generating functions in area and perimeter va riables from the q-series solutions and obtain the scaling functions w here applicable.