Logical characterisations and compositionality of input-output conformance simulation

Abstract

Input-output conformance simulation (iocos) has been pro- posed by Gregorio-Rodr ́ıguez, Llana and Mart ́ınez-Torres as a simulation- based behavioural preorder underlying model-based testing. This relation is inspired by Tretman’s classic ioco relation, but has better worst-case complexity than ioco and supports stepwise refinement. The goal of this paper is to develop the theory of iocos by studying logical characteri- sations of this relation and its compositionality. More specifically, this article presents characterisations of iocos in terms of modal logics and compares them with an existing logical characterisation for ioco pro- posed by Beohar and Mousavi. A precongruence rule format for iocos and a rule format ensuring that operations take quiescence properly into account are also given. Both rule formats are based on the GSOS format by Bloom, Istrail and Meyer.