10.1007/978-3-540-85361-9_14
Krishnendu Chatterjee
Krishnendu
Chatterjee0000-0002-4561-241X
Thomas Henzinger
Thomas A
Henzinger0000−0002−2985−7724
Jobstmann, Barbara
Barbara
Jobstmann
Environment assumptions for synthesis
LNCS
Schloss Dagstuhl - Leibniz-Zentrum für Informatik
2008
2018-12-11T12:05:39Z
2019-08-02T12:38:20Z
conference
https://research-explorer.app.ist.ac.at/record/3877
https://research-explorer.app.ist.ac.at/record/3877.json
The synthesis problem asks to construct a reactive finite-state system from an omega-regular specification. Initial specifications are often unrealizable, which means that there is no system that implements the specification. A common reason for unrealizability is that assumptions on the environment of the system are incomplete. We study the problem of correcting an unrealizable specification phi by computing an environment assumption psi such that the new specification psi -> phi is realizable. Our aim is to construct an assumption psi that constrains only the environment and is as weak as possible. We present a two-step algorithm for computing assumptions. The algorithm operates on the game graph that is used to answer the realizability question. First, we compute a safety assumption that removes a minimal set of environment edges from the graph. Second, we compute a liveness assumption that puts fairness conditions on some of the remaining environment edges. We show that the problem of finding a minimal set of fair edges is computationally hard, and we use probabilistic games to compute a locally minimal fairness assumption.