132 research outputs found
SOS rule formats for convex and abstract probabilistic bisimulations
Probabilistic transition system specifications (PTSSs) in the format provide structural operational semantics for
Segala-type systems that exhibit both probabilistic and nondeterministic
behavior and guarantee that bisimilarity is a congruence for all operator
defined in such format. Starting from the
format, we obtain restricted formats that guarantee that three coarser
bisimulation equivalences are congruences. We focus on (i) Segala's variant of
bisimulation that considers combined transitions, which we call here "convex
bisimulation"; (ii) the bisimulation equivalence resulting from considering
Park & Milner's bisimulation on the usual stripped probabilistic transition
system (translated into a labelled transition system), which we call here
"probability obliterated bisimulation"; and (iii) a "probability abstracted
bisimulation", which, like bisimulation, preserves the structure of the
distributions but instead, it ignores the probability values. In addition, we
compare these bisimulation equivalences and provide a logic characterization
for each of them.Comment: In Proceedings EXPRESS/SOS 2015, arXiv:1508.0634
Divide and Congruence III: Stability & Divergence
In two earlier papers we derived congruence formats for weak semantics on the basis of a decomposition method for modal formulas. The idea is that a congruence format for a semantics must ensure that the formulas in the modal characterisation of this semantics are always decomposed into formulas that are again in this modal characterisation. Here this work is extended with important stability and divergence requirements. Stability refers to the absence of a tau-transition. We show, using the decomposition method, how congruence formats can be relaxed for weak semantics that are stability-respecting. Divergence, which refers to the presence of an infinite sequence of tau-transitions, escapes the inductive decomposition method. We circumvent this problem by proving that a congruence format for a stability-respecting weak semantics is also a congruence format for its divergence-preserving counterpart
Rooted branching bisimulation as a congruence for probabilistic transition systems
Ponencia presentada en el 13 International Workshop on Quantitative Aspects of Programming Languages and Systems. London, United Kingdom, April 11-12, 2015.We propose a probabilistic transition system specification format, referred to as probabilistic RBB safe, for which rooted branching bisimulation is a congruence. The congruence theorem is based on the approach of Fokkink for the qualitative case. For this to work, the theory of transition system specifications in the setting of labeled transition systems needs to be extended to deal with probability distributions, both syntactically and semantically. We provide a scheduler-free characterization of probabilistic branching bisimulation as adapted from work of Andova et al. for the alternating model. Counter examples are given to justify the various conditions required by the format.Fil: Lee, Matías David. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: De Vink, Erik P. Eindhoven University of Technology; The Netherlands.Fil: De Vink, Erik P. Centrum Wiskunde & Informatica; The Netherlands.Ciencias de la Computació
Rooted Divergence-Preserving Branching Bisimilarity is a Congruence
We prove that rooted divergence-preserving branching bisimilarity is a
congruence for the process specification language consisting of nil, action
prefix, choice, and the recursion construct
Delayed choice for process algebra with abstraction
The delayed choice is an operator which serves to combine linear time and branching time within one process algebra. We study this operator in a theory with abstraction, more precisely, in a setting considering branching bisimulation. We show its use in scenario specifications and in verification to reduce irrelevant branching structure of a process
Divergence-Preserving Branching Bisimilarity
This note considers the notion of divergence-preserving branching
bisimilarity. It briefly surveys results pertaining to the notion that have
been obtained in the past one-and-a-half decade, discusses its role in the
study of expressiveness of process calculi, and concludes with some suggestions
for future work.Comment: In Proceedings EXPRESS/SOS 2020, arXiv:2008.1241
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