Permutable agents in process algebras
Within the framework of symmetrical systems, an extension of CCS , so-called PCCS, is described. PCCS equips CCS with the concept of pool of agents by means of the explicit structure of Pool expressions. The symmetries whithin a Pools of agents may then be used to simplify the validation process of concurrent systems.
An equivalence relation, so-called Permutability, is formally introduced: two PCCS expressions are permutable iff they can be obtained from each other by a permutation of expressions within a pool. Permutability can be decided in a polynomial time w.r.t. the length of expressions. The Permutability notion allows the definition of symbolic Processes, which describe the system behaviour when inside a pool the agent identities are removed. A transitional semantics is defined and behavioral verifications may be conducted over symbolic Processes.
Key wordsProcess Algebras Symmetries Concurrent Systems Verification
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