Emiliano Lorini

JAIR Journal 2026 Journal Article

A Rule-based Modal Framework for Causal Reasoning

• Emiliano Lorini

We present a novel rule-based semantics for causal reasoning as well as a number of modal languages interpreted over it. They enable us to represent some fundamental concepts in the theory of causality including causal necessity, causal necessity post-intervention and causal counterfactuals. We provide complexity results for the satisfiability checking and model checking problems for these modal languages. Moreover, we study the relationship between our rule-based semantics and the structural equation modeling (SEM) approach to causal reasoning. Finally, we use our semantics to elucidate the relationship between causal counterfactuals and belief change.

AAAI Conference 2025 Conference Paper

A Computationally Grounded Framework for Cognitive Attitudes

• Tiago de Lima
• Emiliano Lorini
• Elise Perrotin
• François Schwarzentruber

We introduce a novel language for reasoning about agents' cognitive attitudes of both epistemic and motivational type. We interpret it by means of a computationally grounded semantics using belief bases. Our language includes five types of modal operators for implicit belief, complete attraction, complete repulsion, realistic attraction and realistic repulsion. We give an axiomatization and show that our operators are not mutually expressible and that they can be combined to represent a large variety of psychological concepts including ambivalence, indifference, being motivated, being demotivated and preference. We present a dynamic extension of the language that supports reasoning about the effects of belief change operations. Finally, we provide a succinct formulation of model checking for our languages and a PSPACE model checking algorithm relying on a reduction into TQBF. We present some experimental results for the implemented algorithm on computation time in a concrete example.

IJCAI Conference 2025 Conference Paper

A Non-Interventionist Approach to Causal Reasoning Based on Lewisian Counterfactuals

• Carlos Aguilera-Ventura
• Xinghan Liu
• Emiliano Lorini
• Dmitry Rozplokhas

We present a computationally grounded semantics for counterfactual conditionals in which i) the state in a model is decomposed into two elements: a propositional valuation and a causal base in propositional form that represents the causal information available at the state; and ii) the comparative similarity relation between states is computed from the states' two components. We show that, by means of our semantics, we can elegantly formalize the notion of actual cause without recurring to the primitive notion of intervention. Furthermore, we provide a succinct formulation of the model checking problem for a language of counterfactual conditionals in our semantics. We show that this problem is PSPACE-complete and provide a reduction of it into QBF that can be used for automatic verification of causal properties.

AAMAS Conference 2025 Conference Paper

A Simple Integration of Epistemic Logic and Reinforcement Learning

• Thorsten Engesser
• Thibaut Le Marre
• Emiliano Lorini
• François Schwarzentruber
• Bruno Zanuttini

We propose an integration of epistemic logic with reinforcement learning via a semantics that uses the concept of belief bases. In our framework, an agent’s subjective state is identified with their belief base, which captures the agent’s personal representation of the environment. The agent’s subjective state is distinguished from the global state, which captures the overall information about the environment and about the agent’s belief base from an external perspective. We instantiate the concepts of global state and subjective state in Partially-Observable Markov Decision Process (POMDPs), defining so-called Belief Base POMDPs (BB-POMDPs). We show that in our epistemic framework, we can use the beliefs of the learning agent to formalize and implement a natural form of shielding, which prevents agents from performing actions that are not known to be safe. Our implementation of shielding relies on a model-checking algorithm to automatically verify whether a given fact is deducible from the agent’s belief base. We perform a case study of model-free reinforcement learning on a simple wumpus scenario, using a variant of Q-learning on the agent’s subjective states, using the agent’s beliefs for reward shaping and shielding. In particular, our experiments show that our version of shielding can successfully protect the agent from harm while improving the utility of the learned policy.

KR Conference 2025 Conference Paper

An Epistemic Theory of Deductive Arguments

• Emiliano Lorini

Epistemic logic and the theory of argumentation have only very recently started to interact, despite the central role that the epistemic view of argument plays in contemporary epistemology. In this paper, we present a novel epistemic language for reasoning about three types of beliefs of agents: explicit belief, plain implicit belief, and focused implicit belief. We use it to represent the concept of deductive argument and to elucidate its connection with the concept of belief. Our language is interpreted through a formal semantics that relies on belief bases. This semantics allows us to naturally represent the reasons an agent has for believing something, which we show to be closely related to the notion of argument. We provide results on expressiveness, axiomatization and decidability for the language.

TARK Conference 2025 Conference Paper

Graded Distributed Belief

• Emiliano Lorini
• Dmitry Rozplokhas

We introduce a new logic of graded distributed belief that allows us to express the fact that a group of agents distributively believe that a certain fact holds with at least strength k. We interpret our logic by means of computationally grounded semantics relying on the concept of belief base. The strength of the group's distributed belief is directly computed from the group's belief base after having merged its members' individual belief bases. We illustrate our logic with an intuitive example, formalizing the notion of epistemic disagreement. We also provide a sound and complete Hilbert-style axiomatization, decidability result obtained via filtration, and a tableaux-based decision procedure that allows us to state PSPACE-completeness for our logic.

AAMAS Conference 2025 Conference Paper

Rational Capability in Concurrent Games

• Yinfeng Li
• Emiliano Lorini
• Munyque Mittelmann

We extend concurrent game structures (CGSs) with a simple notion of preference over computations and define a minimal notion of rationality for agents based on the concept of dominance. We use this notion to interpret a CL and an ATL languages that extend the basic CL and ATL languages with modalities for rational capability, namely, a coalition’s capability to rationally enforce a given property. For each of these languages, we provide results about the complexity of satisfiability checking and model checking as well as about axiomatization.

IJCAI Conference 2025 Conference Paper

Responsibility Anticipation and Attribution in LTLf

• Giuseppe De Giacomo
• Emiliano Lorini
• Timothy Parker
• Gianmarco Parretti

Responsibility is one of the key notions in machine ethics and in the area of autonomous systems. It is a multi-faceted notion involving counterfactual reasoning about actions and strategies. In this paper, we study different variants of responsibility for LTLf outcomes based on strategic reasoning. We show a connection with notions in reactive synthesis, including the synthesis of winning, dominant, and best-effort strategies. This connection provides a strong computational grounding of responsibility, allowing us to characterize the worst-case computa- tional complexity and devise sound, complete, and optimal algorithms for anticipating and attributing responsibility.

ECAI Conference 2024 Conference Paper

A Novel View of Analogical Proportion Between Formulas

• Andreas Herzig
• Emiliano Lorini
• Henri Prade

Analogical proportions are statements of the form “α is to β as γ is to δ”, noted α: β: :γ: δ, and can be understood as “α differs from β as γ differs from δ” and conversely “β differs from α as δ differs from γ”. In this paper, α, β, γ, δ are supposed to be propositional logic formulas, which are appropriate for representing concepts. There exists one approach, developed over the last 15 years, where “α differs from β” is understood in terms of the negation of the material implication α → β. The paper investigates another view where “α differs from β” is interpreted in terms of transformations where some variables become false, some variables become true, and some variables become irrelevant. Both approaches satisfy the three basic postulates of analogical proportions (reflexivity, symmetry, and stability under central permutation), as well as other interesting properties such as transitivity and unicity of δ such that α: β: :γ: δ. However, the two approaches depart from each other since they do not validate the same analogical proportions. In particular, when p, q, r are atoms the proportion p: (p∧r): :q: (q∧r) holds in the new approach, while it fails to do so for the other. The new approach exhibits also a good behaviour with respect to integrity constraints. It is advocated that this makes it appropriate for handling analogy between concepts, while the other approach has proved to be fruitful for Boolean features-based representations. The paper provides a thorough analysis of the differences between the two approaches.

AAMAS Conference 2024 Conference Paper

Designing Artificial Reasoners for Communication

• Emiliano Lorini

In order to endow a conversational agent with sophisticated social intelligence, machine learning (which is prominent in LLM-based systems like Chat-GPT) is not enough. Logic-based reasoning and decision-making is needed. We need formal languages as well as reasoning and planning algorithms based on them for modeling and endowing the agent with intentional communication, theory of mind, explanatory capability and norm compliance. We identify some requirements that such languages should satisfy as well as a number of challenges regarding their combination and their integration with machine learning methods.

IJCAI Conference 2024 Conference Paper

Model Checking Causality

• Tiago de Lima
• Emiliano Lorini

We present a novel modal language for causal reasoning and interpret it by means of a semantics in which causal information is represented using causal bases in propositional form. The language includes modal operators of conditional causal necessity where the condition is a causal change operation. We provide a succinct formulation of model checking for our language and a model checking procedure based on a polysize reduction to QBF. We illustrate the expressiveness of our language through some examples and show that it allows us to represent and to formally verify a variety of concepts studied in the field of explainable AI including abductive explanation, intervention and actual cause.

EUMAS Conference 2024 Conference Paper

Responsibility in a Multi-value Strategic Setting

• Timothy Parker
• Umberto Grandi
• Emiliano Lorini

Abstract Responsibility is a key notion in multi-agent systems and in creating safe, reliable and ethical AI. In particular, the evaluation of choices based on responsibility is useful for making robustly good decisions in unpredictable domains. However, most previous work on responsibility has only considered responsibility for single outcomes, limiting its application. In this paper we present a model for responsibility attribution in a multi-agent, multi-value setting. We also expand our model to cover responsibility anticipation, demonstrating how considerations of responsibility can help an agent to select strategies that are in line with its values. In particular we show that non-dominated regret-minimising strategies reliably minimise an agent’s expected degree of responsibility.

IJCAI Conference 2023 Conference Paper

A Rule-Based Modal View of Causal Reasoning

• Emiliano Lorini

We present a novel rule-based semantics for causal reasoning as well as a number of modal languages interpreted over it. They enable us to represent some fundamental concepts in the theory of causality including causal necessity and possibility, interventionist conditionals and Lewisian conditionals. We provide complexity results for the satisfiability checking and model checking problem for these modal languages. Moreover, we study the relationship between our rule-based semantics and the structural equation modeling (SEM) approach to causal reasoning, as well as between our rule-based semantics for causal conditionals and the standard semantics for belief base change.

ECAI Conference 2023 Conference Paper

Anticipating Responsibility in Multiagent Planning

• Timothy Parker
• Umberto Grandi
• Emiliano Lorini

Responsibility anticipation is the process of determining if the actions of an individual agent may cause it to be responsible for a particular outcome. This can be used in a multi-agent planning setting to allow agents to anticipate responsibility in the plans they consider. The planning setting in this paper includes partial information regarding the initial state and considers formulas in linear temporal logic as positive or negative outcomes to be attained or avoided. We firstly define attribution for notions of active, passive and contributive responsibility, and consider their agentive variants. We then use these to define the notion of responsibility anticipation. We prove that our notions of anticipated responsibility can be used to coordinate agents in a planning setting and give complexity results for our model, discussing equivalence with classical planning. We also present an outline for solving some of our attribution and anticipation problems using PDDL solvers.

JELIA Conference 2023 Conference Paper

Base-Based Model Checking for Multi-agent only Believing

• Tiago de Lima
• Emiliano Lorini
• François Schwarzentruber

Abstract We present a novel semantics for the language of multi-agent only believing exploiting belief bases, and show how to use it for automatically checking formulas of this language. We provide a PSPACE algorithm for model checking relying on a reduction to QBF, an implementation and some experimental results on computation time in a concrete example.

KR Conference 2023 Conference Paper

Counterfactual Reasoning via Grounded Distance

• Carlos Aguilera-Ventura
• Andreas Herzig
• Xinghan Liu
• Emiliano Lorini

Conditional logics are usually interpreted in terms of closest world and minimal change. It relies on a measure of distance between worlds which is defined abstractly, i. e. as an element of the model. The typical example of a concrete measure in literature is the Hamming distance. We show that given countably infinite atomic propositions in the language, Hamming distance is not merely an example, but grounded for two arguably most important conditional logics, Lewis' VC and VCU. That means, a formula is satisfied in a VC (resp. VCU) model, if and only if it is satisfied in a VC (resp. VCU) model whose distance between worlds is Hammingian.

IJCAI Conference 2023 Conference Paper

Moral Planning Agents with LTL Values

• Umberto Grandi
• Emiliano Lorini
• Timothy Parker

A moral planning agent (MPA) seeks to compare two plans or compute an optimal plan in an interactive setting with other agents, where relative ideality and optimality of plans are defined with respect to a prioritized value base. We model MPAs whose values are expressed by formulas of linear temporal logic (LTL) and define comparison for both joint plans and individual plans. We introduce different evaluation criteria for individual plans including an optimistic (risk-seeking) criterion, a pessimistic (risk-averse) one, and two criteria based on the use of anticipated responsibility. We provide complexity results for a variety of MPA problems.

IJCAI Conference 2022 Conference Paper

A Computationally Grounded Logic of 'Seeing-to-it-that'

• Andreas Herzig
• Emiliano Lorini
• Elise Perrotin

We introduce a simple model of agency that is based on the concepts of control and attempt. Both relate agents and propositional variables. Moreover, they can be nested: an agent i may control whether another agent j controls a propositional variable p; i may control whether j attempts to change p; i may attempt to change whether j controls p; i may attempt to change whether j attempts to change p; and so on. In this framework we define several modal operators of time and agency: the LTL operators on the one hand, and the Chellas and the deliberative stit operator on the other. While in the standard stit framework the model checking problem is unfeasible because its models are infinite, in our framework models are represented in a finite and compact way: they are grounded on the primitive concepts of control and attempt. This makes model checking practically feasible. We prove its PSPACE-completeness and we show how the concept of social influence can be captured.

KR Conference 2022 Conference Paper

Epistemic Actions: Comparing Multi-agent Belief Bases with Action Models

• Emiliano Lorini
• Elise Perrotin
• François Schwarzentruber

We compare the syntactic multi-agent belief base approach, and the dynamic epistemic logic possible world semantic approach. In the belief base approach, the language provides an implicit and an explicit belief operators, plus a dynamic modality for actions consisting in adding formulae to bases. For the semantic approach, we rely on action models of Dynamic Epistemic Logic (DEL). We first show how to translate a formula of the belief base approach into DEL: in particular, we provide a specific action model scheme corresponding to the addition of a formula in a belief base. Conversely, we identify a fragment of DEL that can be translated in the multi- agent belief base language.

AAMAS Conference 2022 Conference Paper

Logical Theories of Collective Attitudes and the Belief Base Perspective

• Emiliano Lorini
• Éloan Rapion

We present two logics of collective belief with a semantics exploiting the notion of belief base. The semantics distinguishes explicit from implicit belief: an agent’s belief of explicit type is a piece of information contained in the agent’s belief base, while a belief of implicit type corresponds to a piece of information that is derivable from the agent’s belief base. The first part of the paper is devoted to the logic of implicit common belief, while the second presents the logic of explicit common belief. Implicit common belief is defined as a mutual belief of any order. This leads to the usual fixpoint construction of common belief. Explicit common belief is the collective counterpart of explicit individual belief and has a public nature. It moreover implies implicit common belief. We study axiomatic aspects of our logics as well as complexity of satisfiability checking. We show that, while the satisfiability checking problem is EXPTIME-hard for the logic of implicit common belief, it is in PSPACE for the logic of explicit common belief. This makes the latter logic a natural candidate for reasoning about collective attitudes in multi-agent scenarios and applications. We also study a dynamic extension of the logic of explicit common belief in which private and public forms of information dynamics can be modeled.

JELIA Conference 2021 Conference Paper

A Computationally Grounded Logic of Graded Belief

• Emiliano Lorini
• François Schwarzentruber

Abstract We present a logic of graded beliefs with a formal semantics grounded on the notion of belief base. It has modal operators which represent what an agent would believe if she removed k pieces of information from her belief base. We provide a sound and complete axiomatics for our logic as well as an optimal model checking algorithm. To illustrate its expressive power, we apply it to modeling social influence and epistemic explanation.

AAMAS Conference 2021 Conference Paper

A Logic of Evaluation

• Emiliano Lorini

We present a logic of evaluation which clarifies the relationship between knowledge, values and preferences of multiple agents in an interactive setting. Evaluation is a fundamental concept for understanding how an ethical agent’s decision is affected by her values. We provide a complete axiomatics for the logic and present a dynamic extension by the concept of value expansion. We show that value expansion indirectly affects the agents’ preferences by inducing a preference upgrade operation.

AAAI Conference 2021 Conference Paper

A Simple Framework for Cognitive Planning

• Jorge Luis Fernandez Davila
• Dominique Longin
• Emiliano Lorini
• Frédéric Maris

We present a novel approach to cognitive planning, i. e. , an agent’s planning aimed at changing the cognitive attitudes of another agent including her beliefs and intentions. We encode the cognitive planning problem in an epistemic logic with a semantics exploiting belief bases. We study a NP-fragment of the logic whose satisfiability problem is reduced to SAT. We provide complexity results for the cognitive planning problem. Moreover, we illustrate its potential for applications in human-machine interaction in which an artificial agent is expected to interact with a human agent through dialogue and to persuade the human to behave in a certain way.

IJCAI Conference 2021 Conference Paper

Multi-Agent Belief Base Revision

• Emiliano Lorini
• Francois Schwarzentruber

We present a generalization of belief base revision to the multi-agent case. In our approach agents have belief bases containing both propositional beliefs and higher-order beliefs about their own beliefs and other agents’ beliefs. Moreover, their belief bases are split in two parts: the mutable part, whose elements may change under belief revision, and the core part, whose elements do not change. We study a belief revision operator inspired by the notion of screened revision. We provide complexity results of model checking for our approach as well as an optimal model checking algorithm. Moreover, we study complexity of epistemic planning formulated in the context of our framework.

ECAI Conference 2020 Conference Paper

A Logic of Explicit and Implicit Distributed Belief

• Andreas Herzig
• Emiliano Lorini
• Elise Perrotin
• Fabián Romero
• François Schwarzentruber

We present a new logic of explicit and implicit distributed belief with a formal semantics exploiting the notion of belief base. A coalition’s distributed belief of explicit type corresponds to a piece of information contained in the collective belief base of the coalition, which is obtained by pooling together the individual belief bases of its members. A coalition’s distributed belief of implicit type corresponds to a piece of information that is derivable from the collective belief base of the coalition. We study axiomatic aspects of our logic as well as complexity of model checking. As distributed belief can be inconsistent (contrary to distributed knowledge), we also study a consistency-preserving variant of distributed belief inspired by the literature on belief merging.

AIJ Journal 2020 Journal Article

Rethinking epistemic logic with belief bases

• Emiliano Lorini

IJCAI Conference 2020 Conference Paper

TouIST: a Friendly Language for Propositional Logic and More

• Jorge Fernandez
• Olivier Gasquet
• Andreas Herzig
• Dominique Longin
• Emiliano Lorini
• Frédéric Maris
• Pierre Régnier

This work deals with logical formalization and problem solving using automated solvers. We present the automatic translator TouIST that provides a simple language to generate logical formulas from a problem description. Our tool allows us to model many static or dynamic combinatorial problems and to benefit from the regular improvements of SAT, QBF or SMT solvers in order to solve these problems efficiently. In particular, we show how to use TouIST to solve different classes of planning tasks in Artificial Intelligence.

AAMAS Conference 2019 Conference Paper

Decision Procedures for Epistemic Logic Exploiting Belief Bases

• Emiliano Lorini
• Fabian Romero

We provide tableau-based PSPACE satisfiability checking procedures for a family of multi-agent epistemic logics with a semantics defined in terms of belief bases. Such logics distinguish an agent’s explicit beliefs, i. e. , all facts included in the agent’s belief base, from the agent’s implicit beliefs, i. e. , all facts deducible from the agent’s belief base. We provide a simple dynamic extension for one of these logics by propositional assignments performed by agents. A propositional assignment captures a simple form of action that changes not only the environment but also the agents’ beliefs depending on how they jointly perceive its execution. After having provided a PSPACE satisfiability checking procedure for this dynamic extension, we show how it can be used in human-robot interaction in which both the human and the robot have higher-order beliefs about the other’s beliefs and can modify the environment by acting.

TARK Conference 2019 Conference Paper

Exploiting Belief Bases for Building Rich Epistemic Structures

• Emiliano Lorini

We introduce a semantics for epistemic logic exploiting a belief base abstraction. Differently from existing Kripke-style semantics for epistemic logic in which the notions of possible world and epistemic alternative are primitive, in the proposed semantics they are non-primitive but are defined from the concept of belief base. We show that this semantics allows us to define the universal epistemic model in a simpler and more compact way than existing inductive constructions of it. We provide (i) a number of semantic equivalence results for both the basic epistemic language with "individual belief" operators and its extension by the notion of "only believing", and (ii) a lower bound complexity result for epistemic logic model checking relative to the universal epistemic model.

JELIA Conference 2019 Conference Paper

Reasoning About Cognitive Attitudes in a Qualitative Setting

• Emiliano Lorini

Abstract We present a general logical framework for reasoning about agents’ cognitive attitudes of both epistemic type and motivational type. We provide a sound and complete axiomatization for our logic and we show that it allows us to express a variety of relevant concepts for qualitative decision theory including the concepts of knowledge, belief, strong belief, conditional belief, desire, strong desire, comparative desirability and choice.

AAMAS Conference 2019 Conference Paper

Strategic Majoritarian Voting with Propositional Goals

• Arianna Novaro
• Umberto Grandi
• Dominique Longin
• Emiliano Lorini

We study strategic behaviour in goal-based voting, where agents take a collective decision over multiple binary issues based on their individual goals (expressed as propositional formulas). We focus on three generalizations of the issue-wise majority rule, and study their resistance to manipulability in the general case, as well as for restricted languages for goals. We also study how computationally hard it is for an agent to know if they can profitably manipulate.

IJCAI Conference 2019 Conference Paper

Stratified Evidence Logics

• Philippe Balbiani
• David Fernández-Duque
• Andreas Herzig
• Emiliano Lorini

Evidence logics model agents' belief revision process as they incorporate and aggregate information obtained from multiple sources. This information is captured using neighbourhood structures, where individual neighbourhoods represent pieces of evidence. In this paper we propose an extended framework which allows one to explicitly quantify either the number of evidence sets, or effort, needed to justify a given proposition, provide a complete deductive calculus and a proof of decidability, and show how existing frameworks can be embedded into ours.

AAMAS Conference 2018 Conference Paper

Concurrent Game Structures for Temporal STIT Logic

• Joseph Boudou
• Emiliano Lorini

The paper introduces a new semantics for temporal STIT logic (the logic of seeing to it that) based on concurrent game structures (CGSs), thereby strengthening the connection between temporal STIT and existing logics for MAS including coalition logic, alternating-time temporal logic and strategy logic whose language are usually interpreted over CGSs. Moreover, it provides a complexity result for a rich temporal STIT language interpreted over these structures. The language extends that of full computation tree logic (CTL∗) by individual agency operators, allowing to express sentences of the form “agent i sees to it that φ is true, as a consequence of her choice”.

AAMAS Conference 2018 Conference Paper

From Individual Goals to Collective Decisions

• Arianna Novaro
• Umberto Grandi
• Dominique Longin
• Emiliano Lorini

We introduce the problem of aggregating the individual goals of a group of agents to find a collective decision. Goals are represented by propositional formulas on a finite set of binary issues. We define some rules for carrying out the aggregation of goals and we show how to adapt axiomatic properties from the literature on Social Choice Theory to this setting. The type of problems we are interested in studying for our rules are axiomatic characterizations, as well as the computational complexity of computing the outcome.

IJCAI Conference 2018 Conference Paper

Goal-Based Collective Decisions: Axiomatics and Computational Complexity

• Arianna Novaro
• Umberto Grandi
• Dominique Longin
• Emiliano Lorini

We study agents expressing propositional goals over a set of binary issues to reach a collective decision. We adapt properties and rules from the literature on Social Choice Theory to our setting, providing an axiomatic characterisation of a majority rule for goal-based voting. We study the computational complexity of finding the outcome of our rules (i. e. , winner determination), showing that it ranges from Nondeterministic Polynomial Time (NP) to Probabilistic Polynomial Time (PP).

AAAI Conference 2018 Conference Paper

In Praise of Belief Bases: Doing Epistemic Logic Without Possible Worlds

• Emiliano Lorini

We introduce a new semantics for a logic of explicit and implicit beliefs based on the concept of multi-agent belief base. Differently from existing Kripke-style semantics for epistemic logic in which the notions of possible world and doxastic/epistemic alternative are primitive, in our semantics they are non-primitive but are defined from the concept of belief base. We provide a complete axiomatization and a decidability result for our logic.

AAMAS Conference 2017 Conference Paper

A Path in the Jungle of Logics for Multi-agent System: On the Relation between General Game-playing Logics and Seeing-to-it-that Logics

• Emiliano Lorini
• Franç ois Schwarzentruber

In the recent years, several concurrent logical systems for reasoning about agency and social interaction and for representing game properties have been proposed. The aim of the present paper is to put some order in this ‘jungle’ of logics by studying the relationship between the dynamic logic of agency DLA and the game description language GDL. The former has been proposed as a variant of the logic of agency STIT in which agents’ action are named, while the latter has been introduced in AI as a formal language for reasoning about general game-playing. The paper provides complexity results for the satisfiability problems of both DLA and GDL as well as a polynomial embedding of GDL into DLA.

AAMAS Conference 2017 Conference Paper

Exploring the Bidimensional Space: A Dynamic Logic Point of View

• Philippe Balbiani
• David Ferná ndez-Duque
• Emiliano Lorini

We present a family of logics for reasoning about agents’ positions and movements in the plane which have several potential applications in the area of multi-agent systems, such as multi-agent planning and robotics. The most general logic includes (i) atomic formulas for representing the truth of a fact or the presence of an agent at a certain position of the plane, (ii) atomic programs corresponding to the four basic orientations in the plane (up, down, left, right) as well as the four program constructs of propositional dynamic logic PDL (sequential composition, nondeterministic composition, iteration and test). As this logic is not computably enumerable, we study some interesting decidable and axiomatizable fragments of it. We also present a decidable extension of its iteration-free fragment by special programs representing movements of agents in the plane.

FLAP Journal 2017 Journal Article

Logics for Games, Emotions and Institutions.

• Emiliano Lorini

We give an informal overview of the way logic and game theory have been used in the past and are currently used to model cognitive agents and multi-agent systems (MAS). In the first part of the paper we consider formal models of mental attitudes and emotions, while in the second part we move from mental attitudes to institutions via collective attitudes.

AAMAS Conference 2017 Conference Paper

Other-Condemning Anger = Blaming Accountable Agents for Unattainable Desires

• Mehdi Dastani
• Emiliano Lorini
• John-Jules Meyer
• Alexander Pankov

TARK Conference 2017 Conference Paper

Relaxing Exclusive Control in Boolean Games

• Francesco Belardinelli
• Umberto Grandi
• Andreas Herzig
• Dominique Longin
• Emiliano Lorini
• Arianna Novaro
• Laurent Perrussel

In the typical framework for boolean games (BG) each player can change the truth value of some propositional atoms, while attempting to make her goal true. In standard BG goals are propositional formulas, whereas in iterated BG goals are formulas of Linear Temporal Logic. Both notions of BG are characterised by the fact that agents have exclusive control over their set of atoms, meaning that no two agents can control the same atom. In the present contribution we drop the exclusivity assumption and explore structures where an atom can be controlled by multiple agents. We introduce Concurrent Game Structures with Shared Propositional Control (CGS-SPC) and show that they ac- count for several classes of repeated games, including iterated boolean games, influence games, and aggregation games. Our main result shows that, as far as verification is concerned, CGS-SPC can be reduced to concurrent game structures with exclusive control. This result provides a polynomial reduction for the model checking problem of specifications in Alternating-time Temporal Logic on CGS-SPC.

AAMAS Conference 2017 Conference Paper

Strategic Disclosure of Opinions on a Social Network

• Umberto Grandi
• Emiliano Lorini
• Arianna Novaro
• Laurent Perrussel

This paper starts from a simple model of strategic reasoning in situations of social influence. Agents express binary views on a set of propositions, and iteratively update their views by taking into account the expressed opinion of their influencers. We empower agents with the ability to disclose or hide their opinions, in order to attain a predetermined goal. We study classical game-theoretic solution concepts in the resulting games, observing a non-trivial interplay between the individual goals and the structure of the underlying network. By making use of different logics for strategic reasoning, we show how apparently simple problems in strategic opinion diffusion require a complex logical machinery to be properly formalized and handled.

IJCAI Conference 2017 Conference Paper

The Ceteris Paribus Structure of Logics of Game Forms (Extended Abstract)

• Davide Grossi
• Emiliano Lorini
• François Schwarzentruber

We present a simple Ceteris Paribus Logic (CP) and study its relationship with existing logics that deal with the representation of choice and power in games in normal form including atemporal STIT, Coalition Logic of Propositional Control (CL-PC) and Dynamic Logic of Propositional Assignments (DL-PA). Thanks to the polynomial reduction of the satisfiability problem for atemporal STIT in the satisfiability problem for CP, we obtain a complexity result for the latter problem.

AAMAS Conference 2016 Conference Paper

A Logical Theory of Belief Dynamics for Resource-Bounded Agents

• Philippe Balbiani
• David Fernández-Duque
• Emiliano Lorini

The paper presents a new logic for reasoning about the formation of beliefs through perception or through inference in non-omniscient resource-bounded agents. The logic distinguishes the concept of explicit belief from the concept of background knowledge. This distinction is reflected in its formal semantics and axiomatics: (i) we use a non- standard semantics putting together a neighbourhood semantics for explicit beliefs and relational semantics for background knowledge, and (ii) we have specific axioms in the logic highlighting the relationship between the two concepts. Mental operations of perceptive type and inferential type, having effects on epistemic states of agents, are primitives in the object language of the logic. At the semantic level, they are modelled as special kinds of model-update operations, in the style of dynamic epistemic logic (DEL). Results about axiomatization, decidability and complexity for the logic are given in the paper.

KR Conference 2016 Conference Paper

Building epistemic logic from observationsand public announcements

• Tristan Charrier
• Andreas Herzig
• Emiliano Lorini
• Faustine Maffre
• Francois Schwarzentruber

As to the first problem, we adopt the solution of (Herzig, We study an epistemic logic where knowledge is built from what the agents observe (including higher-order visibility) and what the agents learn from public announcements. This fixes two main drawbacks of previous observability-based approaches where who sees what is common knowledge and where the epistemic operators distribute over disjunction. The latter forbids the modeling of most of the classical epistemic problems, starting with the muddy children puzzle. We integrate a dynamic dimension where both facts of the world and the agents’ observability can be modified by assignment programs. We establish that the model checking problem is PS PACE-complete.

JELIA Conference 2016 Conference Paper

Decidability and Expressivity of Ockhamist Propositional Dynamic Logics

• Joseph Boudou
• Emiliano Lorini

Abstract Ockhamist Propositional Dynamic Logic ( \(\mathsf {OPDL}\) ) is a logic unifying the family of dynamic logics and the family of branching-time temporal logics, two families of logic widely used in AI to model reactive systems and multi-agent systems (MAS). In this paper, we present two variants of this logic. These two logics share the same language and differ only in one semantic condition. The first logic embeds Bundled \(\textsf {CTL}^* \) while the second embeds \(\textsf {CTL}^* \). We provide a 2EXPTIME decision procedure for the satisfiability problem of each variant. The decision procedure for the first variant of \(\mathsf {OPDL}\) is based on the elimination of Hintikka sets while the decision procedure for the second variant relies on automata.

IJCAI Conference 2016 Conference Paper

Epistemic Boolean Games Based on a Logic of Visibility and Control

• Andreas Herzig
• Emiliano Lorini
• Faustine Maffre
• Francois Schwarzentruber

We analyse epistemic boolean games ina computationally grounded dynamic epistemic logic. The agents' knowledge is determined by what they see, including higher-order visibility: agents may observe whether another agent observes an atom or not. The agents' actions consist in modifying the truth values of atoms. We provide an axiomatisation of the logic, establish that the model checking problem is in PSPACE, and show how one can reason about equilibria in epistemic boolean games.

AAMAS Conference 2016 Conference Paper

Strategic Disclosure of Opinions on a Social Network (Extended Abstract)

• Umberto Grandi
• Emiliano Lorini
• Laurent Perrussel

LORI Conference 2015 Conference Paper

A Poor Man's Epistemic Logic Based on Propositional Assignment and Higher-Order Observation

• Andreas Herzig
• Emiliano Lorini
• Faustine Maffre

Abstract We introduce a dynamic epistemic logic that is based on what an agent can observe, including joint observation and observation of what other agents observe. This generalizes van der Hoek, Wooldridge and colleague’s logics ECL-PC(PO) and LRC where it is common knowledge which propositional variables each agent observes. In our logic, facts of the world and their observability can both be modified by assignment programs. We show how epistemic operators can be interpreted in this framework and identify the conditions under which the principles of positive and negative introspection are valid. We also provide a sound and complete axiomatization and prove that the satisfiability problem is PSpace -complete. Finally, we show how public and private announcements can be expressed and illustrate the latter by the gossip spreading problem.

JAIR Journal 2015 Journal Article

The Ceteris Paribus Structure of Logics of Game Forms

• Davide Grossi
• Emiliano Lorini
• Francois Schwarzentruber

The article introduces a ceteris paribus modal logic, called CP, interpreted on the equivalence classes induced by finite sets of propositional atoms. This logic is studied and then used to embed three logics of strategic interaction, namely atemporal STIT, the coalition logic of propositional control (CL−PC) and the starless fragment of the dynamic logic of propositional assignments (DL−PA). The embeddings highlight a common ceteris paribus structure underpinning the key operators of all these apparently very different logics and show, we argue, remarkable similarities behind some of the most influential formalisms for reasoning about strategic interaction

ECAI Conference 2014 Conference Paper

Trust-based belief change

• Emiliano Lorini
• Guifei Jiang
• Laurent Perrussel

We propose a modal logic that supports reasoning about trust-based belief change. The term trust-based belief change refers to belief change that depends on the degree of trust the receiver has in the source of information.

TARK Conference 2013 Conference Paper

Ceteris Paribus Structure in Logics of Game Forms

• Davide Grossi
• Emiliano Lorini
• François Schwarzentruber

Structure of the paper. The article introduces a ceteris paribus modal logic interpreted on the equivalence classes induced by sets of propositional atoms. This logic is used to embed two logics of agency and games, namely atemporal STIT and the coalition logic of propositional control (CL−PC). The embeddings highlight a common ceteris paribus structure underpinning the key modal operators of both logics, they clarify the relationship between STIT and CL−PC, and enable the transfer of complexity results to the ceteris paribus logic. Section 2 introduces a logic called propositional equivalence ceteris paribus logic (PECP in short), which will be used as yardstick to analyze the game logics addressed in the paper. The logic will be axiomatized and briefly compared with existing modal logics of ceteris paribus reasoning. Section 3 provides a study of the relationship between the atemporal version of STIT and PECP. We show that PECP embeds atemporal group STIT—the fragment of atemporal STIT in which both actions of individuals and groups are represented—under the assumption that the agents’ choices are bounded. We call the latter atemporal ‘bounded’ group STIT. Moreover, we show that PECP embeds atemporal individual STIT—the variant of atemporal STIT in which only the actions of individuals are represented. The former embedding is used to transfer complexity results to PECP. We also present an embedding in PECP of a variant of atemporal group STIT in which groups are nested (i. e. , given two sets of agents J and J 0 either J ⊆ J 0 or viceversa). Section 4 provides an embedding of coalition logic of propositional control into atemporal ‘bounded’ group STIT and, indirectly, it provides an embedding of coalition logic of propositional control into PECP. We conclude in Section 5. Longer proofs are collected in a technical appendix at the end of the paper.

LORI Conference 2013 Conference Paper

Listen to Me! Public Announcements to Agents That Pay Attention - or Not

• Hans van Ditmarsch
• Andreas Herzig
• Emiliano Lorini
• François Schwarzentruber

Abstract In public announcement logic it is assumed that all agents pay attention (listen to/observe) to the announcement. Weaker observational conditions can be modelled in event (action) model logic. In this work, we propose a version of public announcement logic wherein it is encoded in the states of the epistemic model which agents pay attention to the announcement. This logic is called attention-based announcement logic, abbreviated ABAL. We give an axiomatization and prove that complexity of satisfiability is the same as that of public announcement logic, and therefore lower than that of action model logic [2]. We exploit our logic to formalize the concept of joint attention that has been widely discussed in the philosophical and cognitive science literature. Finally, we extend our logic by integrating attention change.

LORI Conference 2013 Conference Paper

Reasoning about Actions Meets Strategic Logics

• Andreas Herzig
• Emiliano Lorini
• Dirk Walther 0002

Abstract We introduce ATLEA, a novel extension of Alternating-time Temporal Logic with explicit actions in the object language. ATLEA allows to reason about abilities of agents under commitments to play certain actions. Pre- and postconditions as well as availability and unavailability of actions can be expressed. We show that the multiagent extension of Reiter’s solution to the frame problem can be encoded into ATLEA. We also consider an epistemic extension of ATLEA. We demonstrate that the resulting logic is sufficiently expressive to reason about uniform choices of actions. Complexity results for the satisfiability problem of ATLEA and its epistemic extension are given in the paper.

AAMAS Conference 2012 Conference Paper

A logic of emotions: from appraisal to coping

• Mehdi Dastani
• Emiliano Lorini

Emotions is a cognitive mechanism that directs an agent's thoughts and attentions to what is relevant, important, and significant. Such a mechanism is crucial for the design of resource-bounded agents that must operate in highly-dynamic, semi-predictable environments and which need mechanisms for allocating their computational resources efficiently. The aim of this work is to propose a logical analysis of emotions and their influences on an agent's behaviour. We focus on four emotion types (viz, hope, fear, joy, and distress) and provide their logical characterizations in a model logic framework. As the intensity of emotion is essential for its influence on an agent's behaviour, the logic is devised to represent and reason about graded beliefs, graded goals and intentions. The belief strength and the goal strength determine the intensity of emotions. Emotions trigger different types of coping strategy which are aimed at dealing with emotions either by forming or revising an intention to act in the world, or by changing the agent's interpretation of the situation (by changing beliefs or goals).

LORI Conference 2011 Conference Paper

A Dynamic Logic of Knowledge, Graded Beliefs and Graded Goals and Its Application to Emotion Modelling

• Emiliano Lorini

Abstract The paper introduces a logic which allows to represent different kinds of mental states of an agent such as knowledge, graded belief, and graded goal, and the notion of epistemic action (as the action of learning that a certain fact φ is true.) The logic is applied to the formalization of expectation-based emotions such as hope, fear, disappointment and relief, and of their intensity.

IJCAI Conference 2011 Conference Paper

A Dynamic Logic of Normative Systems

• Andreas Herzig
• Emiliano Lorini
• Fr
• eacute; d
• eacute; ric Moisan
• Nicolas Troquard

We propose a logical framework to represent and reason about agent interactions in normative systems. Our starting point is a dynamic logic of propositional assignments whose satisfiability problem is PSPACE-complete. We show that it embeds Coalition Logic of Propositional Control CL-PC and that various notions of ability and capability can be captured in it. We illustrate it on a water resource management case study. Finally, we show how the logic can be easily extended in order to represent constitutive rules which are also an essential component of the modelling of social reality.

AIJ Journal 2011 Journal Article

A logic for reasoning about counterfactual emotions

• Emiliano Lorini
• François Schwarzentruber

AAMAS Conference 2011 Conference Paper

Agents That Speak: Modelling Communicative Plans and Information Sources in a Logic of Announcements

• Philippe Balbiani
• Nadine Guiraud
• Andreas Herzig
• Emiliano Lorini

We present a modal logic of belief and announcements in a multi-agent setting. This logic allows to express not only that ψ holds after the announcement of φ as in standard public announcement logic (PAL), but also that the announcement of φ occurs. We use the logic to provide a formal analysis of several concepts that are relevant for multi-agent systems (MAS) theory and applications: the notions of communicative action (an agent informs another agent about something) and communicative intention (an agent has the intention to inform another agent about something), and the notion of information source.

AAMAS Conference 2011 Conference Paper

The Face of Emotions: A Logical Formalization of Expressive Speech Acts

• Nadine Guiraud
• Dominique Longin
• Emiliano Lorini
• Sylvie Pesty
• J
• eacute; r
• eacute; my Rivi
• egrave; re

In this paper, we merge speech act theory, emotion theory, and logic. We propose a modal logic that integrates the concepts of belief, goal, ideal and responsibility and that allows to describe what a given agent expresses in the context of a conversation with another agent. We use the logic in order to provide a systematic analysis of expressive speech acts, that is, speech acts that are aimed at expressing a given emotion (e. g. to apologize, to thank, to reproach, etc. ).

ECAI Conference 2010 Conference Paper

A Logical Model of Intention and Plan Dynamics

• Emiliano Lorini
• Hans van Ditmarsch
• Tiago de Lima

We propose a formal semantics of intention and plan dynamics based on the notion of local assignment. The function of a local assignment is to change the truth value of a given proposition at a specific time point along a history. We combine a static modal logic including a temporal modality and modal operators for mental attitudes belief and choice, with three kinds of dynamic modalities and corresponding three kinds of local assignments operating on agent's beliefs, on agent's choices and on the physical world. An agent's intention is defined in our approach as the agent's choice to perform a given action at a certain time point in the future and two operations called intention generation and intention reconsideration are defined as specific kinds of local assignments on choices. In Section 1 we introduce a static logic of time, action, and mental attitudes. In Section 2 we add the dynamic notion of local assignment to the logic of Section 1. In Section 3, we focus on two specific kinds of local assignment on choice which allow to model the processes of intention and plan generation and reconsideration.

ECAI Conference 2010 Conference Paper

Trust in complex actions

• Julien Bourdon
• Guillaume Feuillade
• Andreas Herzig
• Emiliano Lorini

IJCAI Conference 2009 Conference Paper

• Emiliano Lorini
• François Schwarzentruber

The aim of this work is to propose a logical framework for the specification of cognitive emotions that are based on counterfactual reasoning about agents’ choices. An example of this kind of emotions is regret. In order to meet this objective, we exploit the well-known STIT logic [Belnap et al. , 2001; Horty, 2001]. STIT logic has been proposed in the domain of formal philosophy in the nineties and, more recently, it has been imported into the field of theoretical computer science where its formal relationships with other logics for multiagent systems such as ATL and Coalition Logic (CL) have been studied. STIT is a very suitable formalism to reason about choices and capabilities of agents and groups of agents. Unfortunately, the version of STIT with agents and groups has been recently proved to be undecidable. In this work we study a decidable fragment of STIT with agents and groups which is sufficiently expressive for our purpose of formalizing counterfactual emotions.

LORI Conference 2009 Conference Paper

Dynamic Context Logic

• Guillaume Aucher
• Davide Grossi
• Andreas Herzig
• Emiliano Lorini

Abstract Building on a simple modal logic of context, the paper presents a dynamic logic characterizing operations of contraction and expansion on theories. We investigate the mathematical properties of the logic, and show how it can capture some aspects of the dynamics of normative systems once they are viewed as logical theories.

LORI Conference 2009 Conference Paper

Epistemic Games in Modal Logic: Joint Actions, Knowledge and Preferences All Together

• Emiliano Lorini
• François Schwarzentruber
• Andreas Herzig

Abstract We propose a modal logic called \(\mathcal{EDLA}\) ( Epistemic Dynamic Logic of Agency ) that allows to reason about epistemic games in strategic form. \(\mathcal{EDLA}\) integrates the concepts of joint action, preference and knowledge. In the first part of the paper we introduce \(\mathcal{EDLA}\) and provide soundness, completeness and complexity results. In the second part we study in \(\mathcal{EDLA}\) the epistemic and rationality conditions of some classical solution concepts like Nash equilibrium and iterated strict dominance. In the last part of the paper we combine \(\mathcal{EDLA}\) with Dynamic Epistemic Logic (DEL) in order to model epistemic game dynamics.

LORI Conference 2009 Conference Paper

Intentions and Assignments

• Emiliano Lorini
• Mehdi Dastani
• Hans van Ditmarsch
• Andreas Herzig
• John-Jules Ch. Meyer

Abstract The aim of this work is propose a logical approach to intention dynamics based on the notion of assignment [3, 7]. The function of an assignment is to associate the truth value of a certain formula ϕ to a propositional atom p. We combine a static modal logic of belief and choice with three kinds of dynamic modalities and corresponding three kinds of assignments: assignments operating on an agent’s beliefs, assignments operating on the agent’s choices and assignments operating on the objective world. An agent’s intention is defined in our approach as the agent’s choice to perform a given action and two basic operations on intentions called intention generation and intention reconsideration are defined as specific kinds of assignments on choices.

KR Conference 2008 Conference Paper

A Logical Account of Institutions: From Acceptances to Norms via Legislators

• Emiliano Lorini
• Dominique Longin

The aim of this paper is to provide a logical framework which enables reasoning about institutions and their dynamics. In our approach an institution is grounded on the acceptances of its members. We devote special emphasis to the role of legislator. We characterize the legislator as the role whose function is the creation and the modification of legal facts (e. g. permissions, obligations, etc.): the acceptance of the legislators that a certain norm is valid ensures that the norm is valid. The second part of the paper is devoted to the logical characterization of two important notions in the domain of legal and social theory: the notion of constitutive rule and the notion of norm of competence. A constitutive rule is a rule which is responsible for the creation of new kinds of (institutional) facts. A norm of competence is a rule which assigns powers to the agents playing certain roles within the institution. We show that norms of competence provide the criteria for institutional change.

AAMAS Conference 2008 Conference Paper

Anchoring Institutions in Agents' Attitudes: Towards a Logical Framework for Autonomous MAS

• Benoit Gaudou
• Dominique Longin
• Emiliano Lorini
• Luca Tummolini

The aim of this paper is to provide a logical framework for the specification of autonomous Multi-Agent Systems (MAS). A MAS is autonomous in so far as it is capable of binding (‘nomos’) itself (‘auto’) independently of any external normative constraint specified by a designer. In particular, a MAS is autonomous if it is able to maintain its social institutions (i. e. rule-governed social practices) only by way of the agents’ attitudes. In order to specify an autonomous MAS, we propose the logic AL (Acceptance Logic) in which the acceptance of a proposition by the agents qua group members (i. e. group acceptance) is introduced. Such propositions are true w. r. t. an institutional context and correspond to facts that are instituted in an attitude-dependent way (i. e. normative and institutional facts). Finally, we contend that the present approach paves the way for a foundation of legal institutions, for studying the interaction between social and legal institutions and, eventually, for understanding and modeling institutional change.

AAMAS Conference 2007 Conference Paper

Delegation and Mental States

• Emiliano Lorini
• Nicolas Troquard
• Andreas Herzig
• Cristiano Castelfranchi

In the recent literature on multiagent systems there have been several proposals of formal systems for reasoning about delegation. Most of these approaches have dealt with the concept of delegation leaving mental states such as beliefs, goals and intentions out of consideration. The aim of this paper is to develop a formal approach for reasoning about delegation by modeling intentions and beliefs of the delegating agent in an explicit way. We present a logic where it is possible to investigate the relations between the concept of Intention to be and the concept of Delegation.

JELIA Conference 2006 Conference Paper

Introducing Attempt in a Modal Logic of Intentional Action

• Emiliano Lorini
• Andreas Herzig
• Cristiano Castelfranchi

Abstract The main objective of this work is to develop a multi-modal logic of Intention and Attempt. We call this logic LIA. All formal results are focused on the notion of attempt. We substitute the dynamic molecular notion action by his atomic constituent attempt and define the former from the latter. The relations between attempts, goals, beliefs and present-directed intentions are studied. A section of the paper is devoted to the analysis of the relations of our modal logic with a situation calculus-style approach.