Gist is a tool that (a) solves the qualitative analysis problem of turn-based
probabilistic games with {\omega}-regular objectives; and (b) synthesizes
reasonable environment assumptions for synthesis of unrealizable
specifications. Our tool provides the first and efficient implementations of
several reduction-based techniques to solve turn-based probabilistic games, and
uses the analysis of turn-based probabilistic games for synthesizing
environment assumptions for unrealizable specifications.
Often one has a preference order among the different systems that satisfy a
given specification. Under a probabilistic assumption about the possible
inputs, such a preference order is naturally expressed by a weighted automaton,
which assigns to each word a value, such that a system is preferred if it
generates a higher expected value.