Olle Haeggstroem, Christof Kuelske Gibbs properties of the fuzzy Potts model on trees and in mean field (83K, LaTeX 2e) ABSTRACT. We study Gibbs properties of the fuzzy Potts model in the mean field case (i.e on a complete graph) and on trees. For the mean field case, a complete characterization of the set of temperatures for which non-Gibbsianness happens is given. The results for trees are somewhat less explicit, but we do show for general trees that non-Gibbsianness of the fuzzy Potts model happens exactly for those temperatures where the underlying Potts model has multiple Gibbs measures.