Counter-strategy guided refinement of GR(1) temporal logic specifications

Abstract

Abstract-The reactive synthesis problem is to find a finitestate controller that satisfies a given temporal-logic specification regardless of how its environment behaves. Developing a formal specification is a challenging and tedious task and initial specifications are often unrealizable. In many cases, the source of unrealizability is the lack of adequate assumptions on the environment of the system. In this paper, we consider the problem of automatically correcting an unrealizable specification given in the generalized reactivity (1) fragment of linear temporal logic by adding assumptions on the environment. When a temporal-logic specification is unrealizable, the synthesis algorithm computes a counter-strategy as a witness. Our algorithm then analyzes this counter-strategy and synthesizes a set of candidate environment assumptions that can be used to remove the counter-strategy from the environment's possible behaviors. We demonstrate the applicability of our approach with several case studies.

Pattern-Based Refinement of Assume-Guarantee Specifications in Reactive Synthesis

“…We extend our work in [4] in several aspects. We improve the scalability of the methods proposed in [4] by showing how a more compact abstraction can be constructed for counterstrategies and strategies.…”

“…We extend our work in [4] in several aspects. We improve the scalability of the methods proposed in [4] by showing how a more compact abstraction can be constructed for counterstrategies and strategies. We extend the forms of patterns that can be synthesized, and show how a similar technique for refining unrealizable specifications can be used to refine the requirements of the system.…”

“…In [4], we showed how an unrealizable specification can be refined by adding assumptions on the environment. The refinement is synthesized step by step guided by counter-strategies.…”

“…In [4] we showed how an unrealizable specification can be refined by adding assumptions on its environment. The core of the method is the synthesis of a set of LTL formulas of special form, called patterns, which hold over all runs of an abstraction of the counter-strategy computed for the unrealizable specification.…”

“…To this end, it is sometimes necessary to refine C 1 's specification by adding guarantees to it. We extend the methods in [4] to be able to refine guarantees as well as assumptions.…”