2-Nested Simulation is not Finitely Equationally Axiomatizable

Abstract

<p>2-nested simulation was introduced by Groote and Vaandrager<br /> [10] as the coarsest equivalence included in completed trace equivalence<br /> for which the tyft/tyxt format is a congruence format. In the linear<br />time-branching time spectrum of van Glabbeek [8], 2-nested simulation<br />is one of the few equivalences for which no finite equational axiomatization<br /> is presented. In this paper we prove that such an axiomatization<br />does not exist for 2-nested simulation.</p><p>Keywords: Concurrency, process algebra, basic CCS, 2-nested simulation,<br /> equational logic, complete axiomatizations.</p>