Distributive Laws and Decidable Properties of SOS Specifications

Some formats of well-behaved operational specifications, correspond to natural transformations of certain types (for example, GSOS and coGSOS laws). These transformations have a common generalization: distributive laws of monads over comonads. We prove that this elegant theoretical generalization has limited practical benefits: it does not translate to any concrete rule format that would be complete for specifications that contain both GSOS and coGSOS rules. This is shown for the case of labeled transition systems and deterministic stream systems.Comment: In Proceedings EXPRESS/SOS 2014, arXiv:1408.127

Ntyft/ntyxt rules reduce to ntree rules

Groote and Vaandrager introduced the tyft/tyxt format for Transition System Specifications (TSSs), and established that for each TSS in this format that is well-founded, the bisimulation equivalence it induces is a congruence. In this paper, we construct for each TSS in tyft/tyxt format an equivalent TSS that consists of tree rules only. As a corollary we can give an affirmative answer to an open question, namely whether the well-foundedness condition in the congruence theorem for tyft/tyxt can be dropped. These results extend to tyft/tyxt with negative premises and predicates

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

An algebraic approach to transactional processes

Abstract We present a set of operators in order to simplify the modelling of transactional behaviour of processes using process algebra. We give an axiomatic semantics of the operators presented. Apart from that, we give their operational semantics using Plotkin-style deduction rules. Our goal is to give formal speci¯cations of Internet applications using process algebra, for which transactional behaviour should be modelled

Duplication of constants in process algebra

The constant 0 (or !, nil ) has different roles in process algebra: on the one hand, it serves as the identity element of alternative composition, on the other hand, it stands for a blocked atomic action or for livelock. When extensions with timing are considered, these roles diverge. We argue that it is better to use two separate constants ¿0 and 0 for the different usages. With respect to the termination constant 1 (or ", skip), the situation is comparable: on the one hand, it serves as the identity element of sequential composition, on the other hand, it serves as the identity element of parallel composition, and stands for a skipped atomic action. We have separate constants ¿1 and 1 for the different usages

The Tyft/tyxt Format Reduces to Tree Rules

. Groote and Vaandrager [5] introduced the tyft/tyxt format for transition system specifications (TSSs), and established that for each TSS in this format that is well-founded, the strong bisimulation it induces is a congruence. In this paper, we construct for each TSS in tyft/tyxt format an equivalent TSS that consists of tree rules only. As a corollary we can give an affirmative answer to an open question, namely whether the well-foundedness condition in the Congruence Theorem of [5] can be dropped. These results extend to tyft/tyxt with negative premises and predicates. 1 Introduction A current method to provide programming and specification languages with an operational semantics is based on the use of transition systems, advocated by Plotkin [7]. Given a set of states, the transitions between these states are obtained inductively from a transition system specification (TSS), containing transition rules. Such a rule, together with a number of transitions, may imply the validity of..