Many analysis and verifications tasks, such as static program analyses and model-checking for temporal logics, reduce to the solution of systems of equations over suitable lattices. Inspired by recent work on lattice-theoretic progress measures, we develop a game-theoretical approach to the solution of systems of monotone equations over lattices, where for each single equation either the least or greatest solution is taken. A simple parity game, referred to as fixpoint game, is defined that provides a correct and complete characterisation of the solution of systems of equations over continuous lattices, a quite general class of lattices widely used in semantics. For powerset lattices the fixpoint game is intimately connected with classical parity games for $\mu$-calculus model-checking, whose solution can exploit as a key tool Jurdziński’s small progress measures. We show how the notion of progress measure can be naturally generalised to fixpoint games over continuous lattices and we prove the existence of small progress measures. Our results lead to a constructive formulation of progress measures as (least) fixpoints. We refine this characterisation by introducing the notion of selection that allows one to constrain the plays in the parity game, enabling an effective (and possibly efficient) solution of the game, and thus of the associated verification problem. We also propose a logic for specifying the moves of the existential player that can be used to systematically derive simplified equations for efficiently computing progress measures. We discuss potential applications to the model-checking of latticed $\mu$-calculi.
Fri 18 Jan
|13:45 - 14:07|
Wen KokkeUniversity of Edinburgh, Fabrizio MontesiUniversity of Southern Denmark, Marco PeressottiUniversity of Southern DenmarkLink to publication DOI Media Attached
|14:07 - 14:29|
Filippo BonchiUniversity of Pisa, Joshua HollandUniversity of Southampton, Robin PiedeleuUniversity of Oxford, Pawel SobocinskiUniversity of Southampton, Fabio ZanasiUniversity College LondonLink to publication DOI Media Attached
|14:29 - 14:51|
Paolo BaldanUniversity of Padova, Barbara KönigUniversity of Duisburg-Essen, Christina Mika-MichalskiUniversity of Duisburg-Essen, Tommaso PadoanUniversity of PadovaLink to publication DOI Media Attached File Attached