760,249 research outputs found
Towards an Updatable Strategy Logic
This article is about temporal multi-agent logics. Several of these
formalisms have been already presented (ATL-ATL*, ATLsc, SL). They enable to
express the capacities of agents in a system to ensure the satisfaction of
temporal properties. Particularly, SL and ATLsc enable several agents to
interact in a context mixing the different strategies they play in a semantical
game. We generalize this possibility by proposing a new formalism, Updating
Strategy Logic (USL). In USL, an agent can also refine its own strategy. The
gain in expressive power rises the notion of "sustainable capacities" for
agents.
USL is built from SL. It mainly brings to SL the two following modifications:
semantically, the successor of a given state is not uniquely determined by the
data of one choice from each agent. Syntactically, we introduce in the language
an operator, called an "unbinder", which explicitely deletes the binding of a
strategy to an agent. We show that USL is strictly more expressive than SL.Comment: In Proceedings SR 2013, arXiv:1303.007
Strategy Logic with Imperfect Information
We introduce an extension of Strategy Logic for the imperfect-information
setting, called SLii, and study its model-checking problem. As this logic
naturally captures multi-player games with imperfect information, the problem
turns out to be undecidable. We introduce a syntactical class of "hierarchical
instances" for which, intuitively, as one goes down the syntactic tree of the
formula, strategy quantifications are concerned with finer observations of the
model. We prove that model-checking SLii restricted to hierarchical instances
is decidable. This result, because it allows for complex patterns of
existential and universal quantification on strategies, greatly generalises
previous ones, such as decidability of multi-player games with imperfect
information and hierarchical observations, and decidability of distributed
synthesis for hierarchical systems. To establish the decidability result, we
introduce and study QCTL*ii, an extension of QCTL* (itself an extension of CTL*
with second-order quantification over atomic propositions) by parameterising
its quantifiers with observations. The simple syntax of QCTL* ii allows us to
provide a conceptually neat reduction of SLii to QCTL*ii that separates
concerns, allowing one to forget about strategies and players and focus solely
on second-order quantification. While the model-checking problem of QCTL*ii is,
in general, undecidable, we identify a syntactic fragment of hierarchical
formulas and prove, using an automata-theoretic approach, that it is decidable.
The decidability result for SLii follows since the reduction maps hierarchical
instances of SLii to hierarchical formulas of QCTL*ii
Reasoning about Knowledge and Strategies: Epistemic Strategy Logic
In this paper we introduce Epistemic Strategy Logic (ESL), an extension of
Strategy Logic with modal operators for individual knowledge. This enhanced
framework allows us to represent explicitly and to reason about the knowledge
agents have of their own and other agents' strategies. We provide a semantics
to ESL in terms of epistemic concurrent game models, and consider the
corresponding model checking problem. We show that the complexity of model
checking ESL is not worse than (non-epistemic) Strategy LogicComment: In Proceedings SR 2014, arXiv:1404.041
MCMAS-SLK: A Model Checker for the Verification of Strategy Logic Specifications
We introduce MCMAS-SLK, a BDD-based model checker for the verification of
systems against specifications expressed in a novel, epistemic variant of
strategy logic. We give syntax and semantics of the specification language and
introduce a labelling algorithm for epistemic and strategy logic modalities. We
provide details of the checker which can also be used for synthesising agents'
strategies so that a specification is satisfied by the system. We evaluate the
efficiency of the implementation by discussing the results obtained for the
dining cryptographers protocol and a variant of the cake-cutting problem
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