Normal Bisimulations in Calculi with Passivation

摘要

Behavioral theory for higher-order process calculi is less well developed than for first-order ones such as the π-calculus. In particular, effective coinductive characterizations of barbed congruence, such as the notion of normal bisimulation developed by Sangiorgi for the higher-order π-calculus, are difficult to obtain. In this paper, we study bisimulations in two simple higher-order calculi with a passivation operator, that allows the interruption and thunkification of a running process. We develop a normal bisimulation that characterizes barbed congruence, in the strong and weak cases, for the first calculus which has no name restriction operator. We then show that this result does not hold in the calculus extended with name restriction.