Guido Governatori

Central Queensland University · School of Engineering and Technology

In this paper we propose an extension of Defeasible Logic to represent and compute three concepts of defeasible permission. In particular, we discuss different types of explicit permissive norms that work as exceptions to opposite obligations. Moreover, we show how strong permissions can be represented both with, and without introducing a new conse...

In this paper we discuss some reasons why temporal logic might not be suitable to model real life norms. To show this, we present a novel deontic logic contrary-to-duty/derived permission paradox based on the interaction of obligations, permissions and contrary-to-duty obligations. The paradox is inspired by real life norms.

In this paper, we explore how, and if, free choice permission (FCP) can be accepted when we consider deontic conflicts between certain types of permissions and obligations. As is well known, FCP can license, under some minimal conditions, the derivation of an indefinite number of permissions. We discuss this and other drawbacks and present six Hilb...

We advance an alternative version of the Chisholm Paradox and we argue that the alternative version (while logically equivalent to the original version), in its manifestation in the natural language, is not intuitively consistent. The alternative version of the paradox suggests some requirements for deontic logics designed for legal reasoning.

We present a novel implementation of Defeasible Deontic Logic as an Answer Set Programming meta-program, and we evaluate the performance of the implementation against a recent set of benchmarks.

We study weak permissions in criminal trials, which require judicial determination due to the absence of explicit prohibitions. We thus sketch a dialogue game to address this issue, analyzing argumentative dynamics with common and private knowledge. By applying various argumentation semantics, we clarify the procedural implications for weak permiss...

We consider the notion of weak permission as the failure to conclude that the opposite obligation. We investigate the issue from the point of non-monotonic reasoning, specifically logic programming and structured argumentation, and we show that it is not possible to capture weak permission in the presence of deontic conflicts under the well-founded...

We consider the notion of weak permission as the failure to conclude that the opposite obligation. We investigate the issue from the point of non-monotonic reasoning, specifically logic programming and structured argumentation, and we show that it is not possible to capture weak permission in the presence of deontic conflicts under the well-founded...

We present a rule-based system to check whether a roster of doctors in a healthcare setting complies with the work conditions mandated by the Italian National Contracts of Employment for medical doctors.

We study weak permissions in criminal trials, which require judicial determination due to the absence of explicit prohibitions. We thus sketch a dialogue game to address this issue, analyzing argumentative dynamics with common and private knowledge. By applying various argumentation semantics, we clarify the procedural implications for weak permiss...

We present a novel implementation of Defeasible Deontic Logic as an Answer Set Programming meta-program, and we evaluate the performance of the implementation against a recent set of benchmarks.

The EU AI Act is the first step toward a comprehensive legal framework for AI. It introduces provisions for AI systems based on their risk levels in relation to fundamental rights. Providers of AI systems must conduct Conformity Assessments before market placement. Recent amendments added Fundamental Rights Impact Assessments for high-risk AI syste...

Event logs capture the execution of business processes, such that each task is represented by an event and each individual execution is a chronological sequence of events, called an event trace. Event logs allow after-the-act and runtime analysis of deployed business processes to verify whether their execution complies with regulations and business...

The use of meta-rules in logic, i.e., rules whose content includes other rules, has recently gained attention in the setting of non-monotonic reasoning: a first logical formalisation and efficient algorithms to compute the (meta)-extensions of such theories were proposed in Olivieri et al. (2021, Computing defeasible meta-logic. In JELIA 2021, LNCS...

This paper reconstructs in the context of formal argumentation the notion of stable explanation developed elsewhere in Defeasible Logic. With this done, we discuss the deontic meaning of this notion and show how to build from argumentation neighborhood structures for deontic logic where a stable explanation can be characterised.

Improving the safety of autonomous vehicles (AVs) by making driving decisions in accordance with traffic rules is a complex task. Traffic rules are often expressed in a way that allows for interpretation and exceptions, making it difficult for AVs to follow them. This paper proposes a novel methodology for driving decision making in AVs based on de...

This paper examines how a notion of stable explanation developed elsewhere in Defeasible Logic can be expressed in the context of formal argumentation. With this done, we discuss the deontic meaning of this reconstruction and show how to build from argumentation neighborhood structures for deontic logic where this notion of explanation can be chara...

We present a defeasible semantics for the CCLAW L4 Domanin Specific Language for legal reasoning using an Answer Set Programming implementation of Defasible Deontic Logic

This article proposes an innovative methodology for enhancing the technical validation, legal alignment and interdisciplinarity of attempts to encode legislation. In the context of an experiment that examines how different legally trained participants convert select provisions of the Australian Copyright Act 1968 (Cth) into machine-executable code,...

This paper analyses and compares some of the automated reasoners that have been used in recent research for compliance checking. Although the list of the considered reasoners is not exhaustive, we believe that our analysis is representative enough to take stock of the current state of the art in the topic. We are interested here in formalizations a...

Automated Vehicles (AVs) are designed and programmed to follow traffic rules. However, there is no separate and comprehensive regulatory framework dedicated to AVs. The current Queensland traffic rules were designed for humans. These rules often contain open texture expressions, exceptions, and potential conflicts (conflict arises when exceptions c...

Paper presented at ProLaLa 2023 Workshop

Counterfactual reasoning has been the subject of extensive study in philosophy, logics, and AI. The connection between counterfactual reasoning and theory revision is well-known since Ramsey’s intuition, according to which “to find out whether the counterfactual ‘if A were true, then B would be true’ is satisfied in a state S, change the state S mi...

Road traffic injuries are one of the primary reasons for death, especially in developing countries like Bangladesh. Safety in land transport is one of the major concerns for road safety authorities and other policymakers. For this reason, contributory factors identification associated with crashes is necessary for reducing road crashes and ensuring...

Modelling the concept of explanation is a central matter in AI systems, as it provides methods for developing eXplainable AI (XAI). When explanation applies to normative reasoning, XAI aims at promoting normative trust in the decisions of AI systems: in fact, such a trust depends on understanding whether systems predictions correspond to legally co...

This paper presents an extension of Defeasible Deontic Logic to deal with the Pragmatic Oddity problem. The logic applies three general principles: (i) the Pragmatic Oddity problem must be solved within a general logical treatment of contrary-to-duty (CTD) reasoning; (ii) non-monotonic methods must be adopted to handle CTD reasoning; (iii) logical...

It is crucial to validate driving behaviour against current road rules to improve Autonomous Vehicle (AV) safety. Validating the AV behaviour is challenging due to the way Queensland Overtaking Road Rules are written, as it includes vague terms and exceptions. This research introduces a Defeasible Deontic Logic (DDL) based framework to validate AV...

Recent years have yielded many discussions on how to endow autonomous agents with the ability to make ethical decisions, and the need for explicit ethical reasoning and transparency is a persistent theme in this literature. We present a modular and transparent approach to equip autonomous agents with the ability to comply with ethical prescriptions...

This work describes a methodological approach to investigate Compliance Management in healthcare based on a BPM perspective, exploring an application in an innovative hospital service. Firstly, we present a business process analysis by modeling the process with the adoption of a standard language. Secondly , we encode a set of rules in LegalRuleML,...

The use of meta-rules in logic, i.e., rules whose content includes other rules, has recently gained attention in the setting of non-monotonic reasoning: a first logical formalisation and efficient algorithms to compute the (meta)-extensions of such theories were proposed in Olivieri et al (2021) This work extends such a logical framework by conside...

This paper presents an extension of Defeasible Deontic Logic to deal with the Pragmatic Oddity problem. The logic applies three general principles: (1) the Pragmatic Oddity problem must be solved within a general logical treatment of CTD reasoning; (2) non-monotonic methods must be adopted to handle CTD reasoning; (3) logical models of CTD reasonin...

A wealth of techniques have been developed to help organizations understand their processes, verify correctness against requirements and diagnose potential problems. In general, these verification techniques allow us to check whether a business process conforms or complies with some specification, and each of them is specifically designed to solve...

The first issue of Artificial Intelligence and Law journal was published in 1992. This paper provides commentaries on landmark papers from the first decade of that journal. The topics discussed include reasoning with cases, argumentation, normative reasoning, dialogue, representing legal knowledge and neural networks.

Healthy farm plant leaf classification and identification is a critical food security issue. In many places of the world, it remains tough as it needs appropriate infrastructure. Combining the rising worldwide prevalence of the smartphone with current progress in computer vision through deep learning, now it is possible to diagnose inconsistency of...

The process of explaining a piece of evidence by constructing a set of assumptions that are a good explanation for that evidence is ubiquitous in real-life (e.g. in legal systems). In this paper, we introduce, discuss, and formalise the notion of stable explanations in a non-monotonic setting. We show how, while applying it to the process of (1) co...

This paper presents an approach for legal compliance checking in the Semantic Web which can be effectively applied for applications in the Linked Open Data environment. It is based on modeling deontic norms in terms of ontology classes and ontology property restrictions. It is also shown how this approach can handle norm defeasibility. Such methodo...

Knowledge representation and reasoning in the legal domain has primarily focused on case studies where knowledge and data can fit in main memory. However, this assumption no longer applies in the era of big data, where large amounts of data are generated daily. This paper discusses new opportunities and challenges that emerge in relation to reasoni...

The spread of respiratory diseases via aerosol particles in indoor settings is of significant concern. The SARS-CoV-2 virus has been found to spread widely in confined enclosures like hotels, hospitals, cruise ships, prisons, and churches. Particles exhaled from a person indoors can remain suspended long enough for increasing the opportunity for pa...

In the last few years, AI continues demonstrating its positive impact on society while sometimes with ethically questionable consequences. Building and maintaining public trust in AI has been identified as the key to successful and sustainable innovation. This chapter discusses the challenges related to operationalizing ethical AI principles and pr...

In this chapter we develop more extensively the logical framework introduced in Malerba et al. (Legal Knowledge and Information Systems - JURIX 2016: The Twenty-Ninth Annual Conference, vol.294 of Frontiers in Artificial Intelligence and Applications, pp. 83–92, IOS Press, 2016) to model reasoning across legal systems. The logic extends the system...

This paper develops a new comprehensive computational framework for reasoning about private international law that encompasses the reasoning patterns modeled by previous works [3,8,9]. The framework is a multi-modal extension of [10] preserving some nice properties of the original system, including some efficient algorithms to compute the extension...

This paper develops a new comprehensive computational framework for reasoning about private international law that encompasses the reasoning patterns modeled by previous works [3,8,9]. The framework is a multi-modal extension of [10] preserving some nice properties of the original system, including some efficient algorithms to compute the extension...

Safety-critical systems manufacturers have the duty of care, i.e., they should take correct steps while performing acts that could foreseeably harm others. Commonly, industry standards prescribe reasonable steps in their process requirements, which regulatory bodies trust. Manufacturers perform careful documentation of compliance with each requirem...

The present paper proposes a structural operational semantics and the related semantics for normative systems. The proposed approach focuses on explicitly representing in force obligations and violations as events in a temporal framework, determining the state of a normative system. In the paper we use a set of core principles, defining some of the...

One of the main issues of every business process is to be compliant with legal rules. This work presents a methodology to check in a semi-automated way the regulatory compliance of a business process. We analyse an e-Health hospital service in particular: the Hospital at Home (HaH) service. The paper shows, at first, the analysis of the hospital bu...

This chapter is a light-weighted overview of significant contributions to legal logic insofar as they involve deontic reasoning and related methods. A special emphasis is given to defeasible reasoning, which has been the major topic for legal reasoning in the last decades. The chapter is divided into three parts and the layout is as follows. Part 1...

Dialogue games are a dynamic form of argumentation, with multiple parties pooling their arguments with the intention of settling an issue. Such games can have a variety of structures, and may be collaborative or competitive, depending on the motivations of the parties. Strategic argumentation is a class of competitive dialogue games in which two pl...

We introduce a modular and transparent approach for augmenting the ability of reinforcement learning agents to comply with a given norm base. The normative supervisor module functions as both an event recorder and real-time compliance checker w.r.t. an external norm base. We have implemented this module with a theorem prover for defeasible deontic...

In the last few years, AI continues demonstrating its positive impact on society while sometimes with ethically questionable consequences. Building and maintaining public trust in AI has been identified as the key to successful and sustainable innovation. This chapter discusses the challenges related to operationalizing ethical AI principles and pr...

The use of meta-rules, i.e., rules whose content includes other rules, has been advocated to model policies and the notion of power in legal reasoning, where an agent has the power to create new norms affecting other agents. The use of Defeasible Logic (DL) to model meta-rules in the application area we just alluded to has been investigated, but no...

Organisations model their processes using so-called business process models, to allow for verification of their correctness with respect to regulatory requirements and business rules. Automated methods for checking compliance, however, have to deal with the high complexity of the requirements as well as the significant size and quantity of process...

Traditionally, computational knowledge representation and reasoning focused its attention on rich domains such as the law. The main underlying assumption of traditional legal knowledge representation and reasoning is that knowledge and data are both available in main memory. However, in the era of big data, where large amounts of data are generated...

A rule based knowledge system consists of three main components: a set of rules, facts to be fed to the reasoning corresponding to the data of a case, and an inference engine. In general, facts are stored in (relational) databases that represent knowledge in a first-order based formalism. However, legal knowledge uses defeasible deontic logic for k...

In order to properly model norm change in the law, temporal aspects of legal dynamics must be considered. Since there exist several time-based features of law that should be studied, we discuss two interesting approaches: one based on defeasible logic and the other based on belief revision. Each of these makes use of one of the two classic forms of...

In the present chapter we focus our attention on the computational complexity of proving regulatory compliance of business process models. While the topic has never received the deserved attention, we argue that the theoretical results, both existing and yet to find, are far reaching for many areas related to the problem of proving compliance of pr...

This three-volume set, LNAI 13031, LNAI 13032, and LNAI 13033 constitutes the thoroughly refereed proceedings of the 18th Pacific Rim Conference on Artificial Intelligence, PRICAI 2021, held in Hanoi, Vietnam, in November 2021. The 93 full papers and 28 short papers presented in these volumes were carefully reviewed and selected from 382 submission...

This three-volume set, LNAI 13031, LNAI 13032, and LNAI 13033 constitutes the thoroughly refereed proceedings of the 18th Pacific Rim Conference on Artificial Intelligence, PRICAI 2021, held in Hanoi, Vietnam, in November 2021. The 93 full papers and 28 short papers presented in these volumes were carefully reviewed and selected from 382 submission...

Free Choice Permission is one of the challenges for the formalisation of norms. In this paper, we follow a novel approach that accepts Free Choice Permission in a restricted form. The intuition behind the guarded form is strongly aligned with the idea of defeasibility. Accordingly, we investigate how to model the guarded form in Defeasible Deontic...

Automatically assessing driving behaviour against traffic rules is a challenging task for improving the safety of Automated Vehicles (AVs). There are no AV specific traffic rules against which AV behaviour can be assessed. Moreover current traffic rules can be imprecisely expressed and are sometimes conflicting making it hard to validate AV driving...

Extracting and formalising legal norms from legal documents is a time-consuming and complex procedure. Therefore, the automatic methods that can accelerate this process are in high demand. In this paper, we address two major questions related to this problem: (i) what are the challenges in formalising legal documents into a machine understandable f...

We discuss how to use Defeasible Deontic Logic to provide a formal representation of the Commonwealth of Australia spent conviction schema (Part VII C of the Crimes Act (1914)). The formalisation is directly written and implemented in Turnip (a modern implementation of Defeasible Deontic Logic).

We explore how, and if, free choice permission (FCP) can be accepted when we consider deontic conflicts between certain types of permissions and obligations. FCP can license, under some minimal conditions, the derivation of an indefinite number of permissions. We discuss this and other drawbacks and present four Hilbert-style classical deontic syst...

We introduce a variant of Deontic Defeasible Logic to handle the issue of Pragmatic Oddity. The key idea is that a conjunctive obligation is allowed only when each individual obligation is independent from the violation of the other obligations. The solution makes essential use of the constructive proof theory of the logic while maintaining a feasi...

We discuss how to use Defeasible Deontic Logic to provide a formal representation of the Commonwealth of Australia spent conviction schema (Part VII C of the Crimes Act (1914)). The formalisation is directly written and implemented in Turnip (a modern implementation of Defeasible Deontic Logic).

This paper introduces a methodology for the encoding of rules into a semantic logical format to facilitate the automated reasoning process. We demonstrate how to identify, capture, combine, and thus formulate all the components from rules into a computationally-oriented formalism. The need for the methodology is motivated by the desire for automate...

In this paper, we present a new methodology to evaluate whether a business process model is fully compliant with a regulatory framework composed of a set of conditional obligations. The methodology is based failure delta-constraints that are evaluated on bottom-up aggregations of a tree-like representation of business process models. While the gene...

We introduce a computational model based on Deontic Defeasible Logic to handle the issue of Pragmatic Oddity. The key idea is that a conjunctive obligation is allowed only when each individual obligation is independent of the violation of the other obligations. The solution makes essential use of the constructive proof theory of the logic.

An approach for legal compliance representation and checking within a Linked Open Data framework is presented. It is based on modeling deontic norms in terms of ontology and ontology property restrictions. It is also shown how the approach can handle norm defeasibility. Such methodology is implemented by de-cidable fragments of OWL 2, while legal r...

We identify some legal reasoning patterns concerning deontic closure and conflicts in defeasible deontic logics. First, whether the logic allows the derivation of permissions from conflicting norms. Second, whether the logic treats norms as closed under logical implication. We suggest appropriate approaches for legal settings.

This paper extends previous work by presenting a framework for modelling legislative deliberation in the form of dialogues with incomplete information. Roughly, in such legislative dialogues coalitions are initially equipped with different theories which constitute their private knowledge. Under this assumption they can dynamically change and propo...

Online Social Networks (OSNs) captured the attention of the masses by offering attractive means of sharing personal information and developing social relationships. People expose personal information about their lives on OSNs. This may result in undesirable consequences of users’ personal information leakage to an unwanted audience and raises priva...

This paper presents a belief revision operator that considers time intervals for modelling norm change in the law. This approach relates techniques from belief revision formalisms and time intervals with temporalised rules for legal systems. Our goal is to formalise a temporalised belief base and corresponding timed derivation, together with a prop...

The social choice theory has focused in the past on the problem of devising methods to determine how individual preferences are transformed into collective ones. In some investigations, scholars provided methods for expressing the social choice function, that, given a set of individual preferences, computes the resulting collective choice. Other st...

Checking regulatory compliance of business processes prior to deployment is common practice and numerous approaches have been developed over the last decade. However, the computational complexity of the problem itself has never received any major attention. Although it is known that the complexity of the problem is generally in NP-complete, many ex...

Linear Logic and Defeasible Logic have been adopted to formalise different features of knowledge representation: consumption of resources, and non monotonic reasoning in particular to represent exceptions. Recently, a framework to combine sub-structural features, corresponding to the consumption of resources, with defeasibility aspects to handle po...

Linear Logic and Defeasible Logic have been adopted to formalise different features of knowledge representation: consumption of resources, and non monotonic reasoning in particular to represent exceptions. Recently, a framework to combine sub-structural features, corresponding to the consumption of resources, with defeasibility aspects to handle po...