21 research outputs found
Reflections on a Geometry of Processes
Contains fulltext :
32919.pdf (publisher's version ) (Open Access)Algebraic Process Calcul
Branching Bisimilarity of Normed BPA Processes is in NEXPTIME
Branching bisimilarity on normed BPA processes was recently shown to be
decidable by Yuxi Fu (ICALP 2013) but his proof has not provided any upper
complexity bound. We present a simpler approach based on relative prime
decompositions that leads to a nondeterministic exponential-time algorithm;
this is close to the known exponential-time lower bound.Comment: This is the same text as in July 2014, but only with some
acknowledgment added due to administrative need
Equivalence-Checking on Infinite-State Systems: Techniques and Results
The paper presents a selection of recently developed and/or used techniques
for equivalence-checking on infinite-state systems, and an up-to-date overview
of existing results (as of September 2004)
Sequencing and intermediate acceptance: Axiomatisation and decidability of bisimilarity
The Theory of Sequential Processes includes deadlock, successful termination, action prefixing, alternative and sequential composition. Intermediate acceptance, which is important for the integration of classical automata theory, can be expressed through a combination of alternative composition and successful termination. Recently, it was argued that complications arising from the interplay between intermediate acceptance and sequential composition can be eliminated by replacing sequential composition by sequencing. In this paper we study the equational theory of the recursion-free fragment of the resulting process theory modulo bisimilarity, proving that it is not finitely based, but does afford a ground-complete axiomatisation if a unary auxiliary operator is added. Furthermore, we prove that bisimilarity is decidable for processes definable by means of a finite guarded recursive specification over the process the
Branching Bisimilarity on Normed BPA Is EXPTIME-complete
We put forward an exponential-time algorithm for deciding branching
bisimilarity on normed BPA (Bacis Process Algebra) systems. The decidability of
branching (or weak) bisimilarity on normed BPA was once a long standing open
problem which was closed by Yuxi Fu. The EXPTIME-hardness is an inference of a
slight modification of the reduction presented by Richard Mayr. Our result
claims that this problem is EXPTIME-complete.Comment: We correct many typing errors, add several remarks and an interesting
toy exampl
Nested Semantics over Finite Trees are Equationally Hard
This paper studies nested simulation and nested trace semantics over the language BCCSP, a basic formalism to express finite process behaviour. It is shown that none of these semantics affords finite (in)equational axiomatizations over BCCSP. In particular, for each of the nested semantics studied in this paper, the collection of sound, closed (in)equations over a singleton action set is not finitely based