  This paper presents a novel technique for state space reduction of
probabilistic specifications, based on a newly developed notion of confluence
for probabilistic automata. We prove that this reduction preserves branching
probabilistic bisimulation and can be applied on-the-fly. To support the
technique, we introduce a method for detecting confluent transitions in the
context of a probabilistic process algebra with data, facilitated by an earlier
defined linear format. A case study demonstrates that significant reductions
can be obtained.
