Summary: Discrete Time Generative­Reactive
Probabilistic Processes with
Di#erent Advancing Speeds
M. Bravetti # , A. Aldini
Universit‘a di Bologna, Dipartimento di Scienze dell'Informazione,
Mura Anteo Zamboni 7, 40127 Bologna, Italy
Abstract
We present a process algebra expressing probabilistic external/internal choices,
multi­way synchronizations, and processes with di#erent advancing speeds in the
context of discrete time, i.e. where time is not continuous but is represented by a
sequence of discrete steps as in Discrete Time Markov Chains (DTMCs). To this
end, we introduce a variant of CSP that employs a probabilistic asynchronous paral­
lel operator whose synchronization mechanism is based on a mixture of the classical
generative and reactive models of probability. In particular, di#erently from existing
discrete time process algebras, where parallel processes are executed in synchronous
locksteps, the parallel operator that we adopt allows processes with di#erent prob­
abilistic advancing speeds (mean number of actions executed per time unit) to be
modeled. Moreover, our generative­reactive synchronization mechanism makes it
possible to always derive DTMCs in the case of fully specified systems. We then
present a sound and complete axiomatization of probabilistic bisimulation over fi­

Source: Aldini, Alessandro - Dipartimento di Matematica, Fisica e Informatica, Universita’ di Urbino "Carlo Bo"

Collections: Computer Technologies and Information Sciences