Summary: ``Next'' Heuristic for On­the­fly Model Checking
Rajeev Alur ? and Bow­Yaw Wang ??
Abstract. We present a new heuristic for on­the­fly enumerative in­
variant verification. The heuristic is based on a construct for temporal
scaling, called next, that compresses a sequence of transitions leading to
a given target set into a single metatransition. First, we give an on­the­
fly algorithm to search a process expression built using the constructs
of hiding, parallel composition, and temporal scaling. Second, we show
that as long the target set \Theta of transitions includes all transitions that
access variables shared with the environment, the process next \Theta for P
and P are equivalent according to the weak­simulation equivalence. As a
result, to search the product of given processes, we can cluster processes
into groups with as little communication among them as possible, and
compose the groups only after applying appropriate hiding and temporal
scaling operators. Applying this process recursively gives an expression
that has multiple nested applications of next, and has potentially much
fewer states than the original product. We report on an implementation,
and show significant reductions for a tree­structured parity computer
and a ring­structured leader­election protocol.
1 Introduction

Source: Alur, Rajeev - Department of Computer and Information Science, University of Pennsylvania

Collections: Computer Technologies and Information Sciences