Abstract On a functor for probabilistic bisimulation and the
preservation of weak pullbacks
Erik de Vink

The preservation of weak pullbacks is studied for a functor M1 on the
category UMS of ultrametric spaces and nonexpansive mappings. The
functor M1 associates with an ultrametric space its collection of Borel
probability measures with compact support. By application of the
Max-flow Min-cut Theorem of graph theory a mediating morphism for a
weak pullback diagram can be constructed in SET. It is shown that the
functor M1 as funtor from UMS to SET preserves weak pullbacks. A
possible solution for the preservation of weak pullback by M1 as
UMS-functor is indicated.