Aniello Murano

University of Naples Federico II | UNINA · Department of Electrical Engineering and Information Technology

We introduce an extension of Strategy logic for the imperfect-information setting, called SL ii , 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...

We study concurrent games with finite-memory strategies where players are given a Buchi and a mean-payoff objective, which are related by a lexicographic order: a player first prefers to satisfy its Buchi objective, and then prefers to minimise costs, which are given by a mean-payoff function. In particular, we show that deciding the existence of a...

We introduce Strategy Logic with Knowledge, a novel formalism to reason about knowledge and strategic ability in memoryless multi-agent systems with incomplete information. We exemplify its expressive power; we define the model checking problem for the logic and show that it is PSpace-complete. We propose a labelling algorithm for solving the verif...

In this paper, for the first time, we study the formal verification of Bayesian mechanisms through strategic reasoning. We rely on the framework of Probabilistic Strategy Logic (PSL), which is well-suited for representing and verifying multi-agent systems with incomplete information. We take advantage of the recent results on the decidability of PS...

In this paper, we study the multi-agent parking problem with time constraints adopting a game-theoretic perspective. Precisely, cars are modeled as agents interacting among themselves in a multi-player game setting, each of which aims to find a free parking slot that satisfies their constraints. We provide an algorithm for assigning parking slots b...

Temporal logics are extensively used for the specification of on-going behaviors of computer systems. Two significant developments in this area are the extension of traditional temporal logics with modalities that enable the specification of on-going strategic behaviors in multi-agent systems, and the transition of temporal logics to a quantitative...

This work is part of a paper accepted at IJCAI-ECAI 22

Mechanism Design aims to design a game so that a desirable outcome is reached regardless of agents' self-interests. In this paper, we show how this problem can be rephrased as a synthesis problem, where mechanisms are automatically synthesized from a partial or complete specification in a high-level logical language. We show that Quantitative Strat...

Do agents know each others’ strategies? In multi-process software construction, each process has access to the processes already constructed; but in typical human-robot interactions, a human may not announce its strategy to the robot (indeed, the human may not even know their own strategy). This question has often been overlooked when modeling and...

In this paper, we propose a game-theoretic solution to the parking problem, by exploiting a strategic-reasoning approach for multi-agent systems. Precisely, cars are modeled by agents interacting among them in a multi-player game setting, whose aim is to get a free slot parking-place satisfying their own constraints. The overall assignment is then...

This paper establishes a framework based on logic and automata theory in which to model and automatically verify systems of multiple mobile agents moving in environments with partially-known topologies, i.e., ones which are not completely known at design time. Examples include physical agents designed to be used in many spatial environments and not...

In online advertising, search engines sell ad placements for keywords continuously through auctions. This problem can be seen as an infinitely repeated game since the auction is executed whenever a user performs a query with the keyword. As advertisers may frequently change their bids, the game will have a large set of equilibria with potentially c...

The overall aim of our research is to develop techniques to reason about the equilibrium properties of multi-agent systems. We model multi-agent systems as concurrent games, in which each player is a process that is assumed to act independently and strategically in pursuit of personal preferences. In this article, we study these games in the contex...

We formally introduce and solve the synthesis problem for LTL goals in the case of multiple, even contradicting, assumptions about the environment. Our solution concept is based on ``best-effort strategies'' which are agent plans that, for each of the environment specifications individually, achieve the agent goal against a maximal set of environme...

Mechanism Design aims at defining mechanisms that satisfy a predefined set of properties, and Auction Mechanisms are of foremost importance. Core properties of mechanisms, such as strategy-proofness or budget-balance, involve: (i) complex strategic concepts such as Nash equilibria, (ii) quantitative aspects such as utilities, and often (iii) imperf...

Trace Alignment is a prominent problem in Declarative Process Mining, which consists in identifying a minimal set of modifications that a log trace (produced by a system under execution) requires in order to be made compliant with a temporal specification. In its simplest form, log traces are sequences of events from a finite alphabet and specifica...

We study the semantics of knowledge in strategic reasoning. Most existing works either implicitly assume that agents do not know one another’s strategies, or that all strategies are known to all; and some works present inconsistent mixes of both features. We put forward a novel semantics for Strategy Logic with Knowledge that cleanly models whose s...

Parity games are infinite-round two-player games played on directed graphs whose nodes are labeled with priorities. The winner of a play is determined by the smallest priority (even or odd) that is encountered infinitely often along the play. In the last two decades, several algorithms for solving parity games have been proposed and implemented in...

Planning domains represent what an agent assumes or believes about the environment it acts in. In the presence of nondeterminism, additional temporal assumptions, such as fairness, are often expressed as extra conditions on the domain. Here we consider environment specifications expressed in arbitrary LTL, which generalize many forms of environment...

We introduce an extension of Strategy Logic for the imperfect-information setting, called SL ii and study its model-checking problem. As this logic naturally captures multi-player games with imperfect information, this problem is undecidable; but we introduce a syntactical class of “hierarchical instances” for which, intuitively, as one goes down t...

We study alternating automata with qualitative semantics over infinite binary trees: Alternation means that two opposing players construct a decoration of the input tree called a run, and the qualitative semantics says that a run of the automaton is accepting if almost all branches of the run are accepting. In this article, we prove a positive and...

Cost-parity games are a fundamental tool in system design for the analysis of reactive and distributed systems that recently have received a lot of attention from the formal methods research community. They allow to reason about the time delay on the requests granted by systems, with a bounded consumption of resources, in their executions. In this...

The paper focuses on automata and linear temporal logics for real-time pushdown reactive systems bridging tractable formalisms specialized for expressing separately dense-time real-time properties and context-free properties though preserving tractability. As for automata, we introduce Event-Clock Nested Automata (ECNA), a formalism that combines E...

In this work, we perform the feasibility analysis of a multi‐grained parallel version of the Zielonka Recursive (ZR) algorithm exploiting the coarse‐ and fine‐ grained concurrency. Coarse‐grained parallelism relies on a suitable splitting of the problem, that is, a graph decomposition based on its Strongly Connected Components (SCC) or a splitting...

We prove the existence and computability of optimal strategies in weighted limit games, zero-sum infinite-duration games with a B\"uchi-style winning condition requiring to produce infinitely many play prefixes that satisfy a given regular specification. Quality of plays is measured in the maximal weight of infixes between successive play prefixes...

We prove the existence and computability of optimal strategies in weighted limit games, zero-sum infinite-duration games with a B\"uchi-style winning condition requiring to produce infinitely many play prefixes that satisfy a given regular specification. Quality of plays is measured in the maximal weight of infixes between successive play prefixes...

The overall aim of our research is to develop techniques to reason about the equilibrium properties of multi-agent systems. We model multi-agent systems as concurrent games, in which each player is a process that is assumed to act independently and strategically in pursuit of personal preferences. In this article, we study these games in the contex...

Strategy Logic with imperfect information (SLiR) is a very expressive logic designed to express complex properties of strategic abilities in distributed systems. Previous work on SLiR focused on finite systems, and showed that the model-checking problem is decidable when information on the control states of the system is hierarchical among the play...

We consider an agent that operates with two models of the environment: one that captures expected behaviors and one that captures additional exceptional behaviors. We study the problem of synthesizing agent strategies that enforce a goal against environments operating as expected while also making a best effort against exceptional environment behav...

Prompt-LTL extends Linear Temporal Logic with a bounded version of the ``eventually'' operator to express temporal requirements such as bounding waiting times. We study assume-guarantee synthesis for prompt-LTL: the goal is to construct a system such that for all environments satisfying a first prompt-LTL formula (the assumption) the system compose...

In this paper, we investigate the module-checking problem of pushdown multi-agent systems (PMS) against ATL and ATL* specifications. We establish that for ATL, module checking of PMS is 2EXPTIME-complete, which is the same complexity as pushdown module-checking for CTL. On the other hand, we show that ATL* module-checking of PMS turns out to be 4EX...

Nondeterministic strategies are strategies (or protocols, or plans) that, given a history in a game, assign a set of possible actions, all of which are winning. An important problem is that of refining such strategies. For instance, given a nondeterministic strategy that allows only safe executions, refine it to, additionally, eventually reach a de...

Model checking multi-agent systems, in which agents are distributed and thus may have different observations of the world, against strategic behaviours is known to be a complex problem in a number of settings. There are traditionally two ways of ameliorating this complexity: imposing a hierarchy on the observations of the agents, or restricting age...

Nowadays, the analysis of vehicular ad hoc networks for the evaluation of traffic conditions is a hot research field. One of the most significant process in VANETs is the vehicle clusterization. Indeed, in order to optimize the information exchange in such a network, an opportune criterion to aggregate vehicles is needed. The main goal of this work...

In this paper, we investigate the module-checking problem of pushdown multi-agent systems (PMS) against ATL and ATL* specifications. We establish that for ATL, module checking of PMS is 2EXPTIME-complete, which is the same complexity as pushdown module-checking for CTL. On the other hand, we show that ATL* module-checking of PMS turns out to be 4EX...

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, this problem is undecidable; but we introduce a syntactical class of "hierarchical instances" for which, intuitively, as one goes down t...

We study alternating automata with qualitative semantics over infinite binary trees: alternation means that two opposing players construct a decoration of the input tree called a run, and the qualitative semantics says that a run of the automaton is accepting if almost all branches of the run are accepting. In this paper we prove a positive and a n...

Dynamic Epistemic Logic (DEL) is a logical framework in which one can describe in great detail how actions are perceived by the agents, and how they affect the world. DEL games were recently introduced as a way to define classes of games with imperfect information where the actions available to the players are described very precisely. This framewo...

We investigate the succinctness gap between two known equally-expressive and different linear-past extensions of standard ATL⁎. We establish by formal non-trivial arguments that the ‘memoryful’ linear-past extension (the history leading to the current state is taken into account) can be exponentially more succinct than the standard ‘local’ linear-p...

Parity games are abstract infinite-round games that take an important role in formal verification. In the basic setting, these games are two-player, turn-based, and played under perfect information on directed graphs, whose nodes are labeled with priorities. The winner of a play is determined according to the parities (even or odd) of the minimal p...

We introduce a logic to reason about strategic abilities in finite games under imperfect information. We interpret Alternating-time Temporal Logic on interpreted systems with final states, where agents only have partial observability of the system’s global state. We consider the model checking problem in this setting. We prove that the complexity r...

Parity games are abstract infinite-duration two-player games, widely studied in computer science to address fundamental questions. Through the years several algorithms to solve parity games have been proposed. Among the others, well known is the Zielonka Recursive (ZR) algorithm. ZR algorithm makes use of a divide and conquer technique in order to...

In game theory, as well as in the semantics of game logics, a strategy can be represented by any function from states of the game to the agent's actions. That makes sense from the mathematical point of view, but not necessarily in the context of human behavior. This is because humans are quite bad at executing complex plans, and rather unlikely to...

This paper introduces Graded Computation Tree Logic with finite path semantics (GCTLf⁎, for short), a variant of Computation Tree Logic CTL⁎, in which path quantifiers are interpreted over finite paths and can count the number of such paths. State formulas of GCTLf⁎ are interpreted over Kripke structures. The syntax of GCTLf⁎ has path quantifiers o...

In this paper we introduce Strategy Logic with simple goals (SL[SG]), a fragment of Strategy Logic that strictly extends the well-known Alternating-time Temporal Logic ATL by introducing arbitrary quantification over the agents' strategies. Our motivation comes from game-theoretic applications, such as expressing Stackelberg equilibria in games, co...

We establish the precise complexity of the model checking problem for the main logics of knowledge and time. While this problem was known to be non-elementary for agents with perfect recall, with a number of exponentials that increases with the alternation of knowledge operators, the precise complexity of the problem when the maximum alternation is...

We introduce and study SL[F], a quantitative extension of SL (Strategy Logic), one of the most natural and expressive logics describing strategic behaviours. The satisfaction value of an SL[F] formula is a real value in [0,1], reflecting ``how much'' or ``how well'' the strategic on-going objectives of the underlying agents are satisfied. We demons...

We introduce Probabilistic Strategy Logic, an extension of Strategy Logic for stochastic systems. The logic has probabilistic terms that allow it to express many standard solution concepts, such as Nash equilibria in randomised strategies, as well as constraints on probabilities, such as independence. We study the model-checking problem for agents...

Planning domains represent what an agent assumes or believes about the environment it acts in. In the presence of nondeterminism, additional temporal assumptions, such as fairness, are often expressed as extra conditions on the domain. Here we consider environment specifications expressed in arbitrary LTL, which generalize many forms of environment...

Temporal logics are extensively used for the specification of on-going behaviours of reactive systems. Two significant developments in this area are the extension of traditional temporal logics with modalities that enable the specification of on-going strategic behaviours in multi-agent systems, and the transition of temporal logics to a quantitati...

We study dynamic changes of agents’ observational power in logics of knowledge and time. We consider CTLK*, the extension of CTL* with knowledge operators, and enrich it with a new operator that models a change in an agent’s way of observing the system. We extend the classic semantics of knowledge for agents with perfect recall to account for chang...

Strategies in game theory and multi-agent logics are mathematical objects of remarkable combinatorial complexity. Recently, the concept of natural strategies has been proposed to model more human-like reasoning about simple plans and their outcomes. So far, the theory of such simple strategic play was only considered in scenarios where all the agen...

VANET constitutes a huge research area due to its potential in traffic management and road safety. In this paper, we propose a novel, smart, and compact representation of vehicular networks. Starting from the standard graph representation, we extract a signal assigning a congestion factor to each vehicle, so that highly jammed traffic areas can be...

We consider an extension of monadic second-order logic, interpreted over the infinite binary tree, by the qualitative path-measure quantifier. This quantifier says that the set of infinite paths in the tree satisfying a formula has Lebesgue-measure one. We prove that this logic is undecidable. To do this we prove that the emptiness problem of quali...

In this paper we introduce Graded Computation Tree Logic over finite paths (GCTL_f* , for short), a variant of Computation Tree Logic CTL* , in which path quantifiers are interpreted over finite paths and can count the number of such paths. State formulas of GCTL_f* are interpreted over Kripke structures with a designated set of states, which we ca...

Two distinct semantics have been considered for knowledge in the context of strategic reasoning, depending on whether players know each other's strategy or not. In the former case, that we call the informed semantics, distributed synthesis for epistemic temporal specifications is undecidable, already on systems with hierarchical information. Howeve...

In this paper we advance the state of the art on the subject of bisimulations for logics of strategies. Bisimulations are a key notion to study the expressive power of a modal language, as well as for applications to system verification. In this contribution we present novel notions of bisimulation for several significant fragments of Strategy Logi...

We investigate the succinctness gap between two known equally-expressive and different linear-past extensions of standard CTL* and ATL*. We establish by formal non-trivial arguments that the 'memoryful' linear-past extension (the history leading to the current state is taken into account) can be exponentially more succinct than the standard 'local'...

The paper is focused on temporal logics for the description of the behaviour of real-time pushdown reactive systems. The paper is motivated to bridge tractable logics specialized for expressing separately dense-time real-time properties and context-free properties by ensuring decidability and tractability in the combined setting. To this end we int...

We introduce Cycle-CTL⋆, an extension of CTL⋆ with cycle quantifications that are able to predicate over cycles. The introduced logic turns out to be very expressive. Indeed, we prove that it strictly extends CTL⋆ and is orthogonal to μCALCULUS. We also give an evidence of its usefulness by providing few examples involving non-regular properties. W...

Program synthesis constructs programs from specifications in an automated way. Strategy Logic (SL) is a powerful and versatile specification language whose goal is to give theoretical foundations for program synthesis in a multi-agent setting. One limitation of Strategy Logic is that it is purely qualitative. For instance it cannot specify quantita...

In this paper we introduce and study Graded Strategy Logic (GSL), an extension of Strategy Logic (SL) with graded quantifiers. SL is a powerful formalism that allows to describe useful game concepts in multi-agent settings by explicitly quantifying over strategies treated as first-order citizens. In GSL, by means of the existential construct, one c...

Strategy Logic (SL) is a logical formalism for strategic reasoning in multi-agent systems. Its main feature is that it has variables for strategies that are associated to specific agents using a binding operator. In this paper we introduce Graded Strategy Logic (GradedSL), an extension of SL by graded quantifiers over tuples of strategy variables,...

In Reasoning about Action and Planning, one synthesizes the agent plan by taking advantage of the assumption on how the environment works (that is, one exploits the environment's effects, its fairness, its trajectory constraints). In this paper we study this form of synthesis in detail. We consider assumptions as constraints on the possible strateg...

In this paper, we introduce a new logic suitable to reason about strategic abilities of multi-agent systems where (teams of) agents are subject to qualitative (parity) and quantitative (energy) con- straints and where goals are represented, as usual, by means of temporal properties. We formally define such a logic, named parity- energy-ATL (pe-ATL,...

We introduce Dynamic Escape Game (DEG), a tool that provides emergency evacuation plans in situations where some of the escape paths may become unavailable at runtime. We formalize the setting as a reachability two-player turn-based game where the universal player has the power of inhibiting at runtime some moves to the existential player. Thus, th...

We develop a logic-based technique to analyse finite interactions in multi-agent systems. We introduce a semantics for Alternating-time Temporal Logic (for both perfect and imperfect recall) and its branching-time fragments in which paths are finite instead of infinite. We study validities of these logics and present optimal algorithms for their mo...

In this paper we provide a broad investigation of the symbolic approach for solving Parity Games. Specifically, we implement in a fresh tool, called Open image in new window , four symbolic algorithms to solve Parity Games and compare their performances to the corresponding explicit versions for different classes of games. By means of benchmarks, w...

Two distinct semantics have been considered for knowledge in the context of strategic reasoning, depending on whether players know each other’s strategy or not. The problem of distributed synthesis for epistemic temporal specifications is known to be undecidable for the latter semantics, already on systems with hierarchical information. However, fo...

Alternating-time Temporal Logic (ATL*) is a central logic for multiagent systems. Its extension to the imperfect information setting (ATL*i ) is well known to have an undecidable model-checking problem when agents have perfect recall. Studies have thus mostly focused either on agents without memory, or on alternative semantics to retrieve decidabil...

Two distinct semantics have been considered for knowledge in the context of strategic reasoning, depending on whether players know each other's strategy or not. The problem of distributed synthesis for epistemic temporal specifications is known to be undecidable for the latter semantics, already on systems with hierarchical information. However, fo...

We study dynamic changes of agents' observational power in logics of knowledge and time. We consider CTL*K, the extension of CTL* with knowledge operators, and enrich it with a new operator that models a change in an agent's way of observing the system. We extend the classic semantics of knowledge for perfect-recall agents to account for changes of...

Graded path modalities count the number of paths satisfying a property, and generalize the existential (E) and universal (A) path modalities of [Figure presented]. The resulting logic is denoted G [Figure presented], and is a powerful logic since (as we show) it is equivalent, over trees, to monadic path logic. We establish the complexity of the sa...

The paper is focused on temporal logics for the description of the behaviour of real-time pushdown reactive systems. The paper is motivated to bridge tractable logics specialized for expressing separately dense-time real-time properties and context-free properties by ensuring decidability and tractability in the combined setting. To this end we int...

The paper is focused on temporal logics for the description of the behaviour of real-time pushdown reactive systems. The paper is motivated to bridge tractable logics specialized for expressing separately dense-time real-time properties and context-free properties by ensuring decidability and tractability in the combined setting. To this end we int...

In game theory, deciding whether a designed player wins a game amounts to check whether he has a winning strategy. However, there are several game settings in which knowing whether he has more than a winning strategy is also important. For example, this is crucial in deciding whether a game admits a unique Nash Equilibrium, or in planning a rescue...

In this paper we introduce and study Event-Clock Nested Automata (ECNA), a formalism that combines Event Clock Automata (ECA) and Visibly Pushdown Automata (VPA). ECNA allow to express real-time properties over non-regular patterns of recursive programs. We prove that ECNA retain the closure and decidability properties of ECA and VPA being closed u...

Ubiquitous computing and contextual services have growing importance in nowadays literature due to the current availability of smart personal devices like smartphones. It is becoming increasingly important to have a reliable way to localize users in any possible scenario. In outdoor it's possible to use GNSS based systems like GPS or GLONASS, but f...

In game theory, deciding whether a designed player wins a game corresponds to check whether he has a winning strategy. There are situations in which it is important to know whether some extra winning strategy also exists. In this paper we investigate this question over two-player turn-based games under safety and fairness objectives. We provide an...