Argumentation Semantics Research Articles

Abstract argumentation frameworks with strong and weak constraints

Dealing with controversial information is an important issue in several application contexts. Formal argumentation enables reasoning on arguments for and against a claim to decide on an outcome. Dung's abstract Argumentation Framework (AF) has emerged as a central formalism in argument-based reasoning. Key aspects of the success and popularity of Dung's framework include its simplicity and expressiveness. Integrity constraints help to express domain knowledge in a compact and natural way, thus keeping easy the modeling task even for problems that otherwise would be hard to encode within an AF. In this paper, we first explore two intuitive semantics based on Kleene and Lukasiewicz logics, respectively, for AF augmented with (strong) constraints—the resulting argumentation framework is called Constrained AF (CAF). Then, we propose a new argumentation framework called Weak constrained AF (WAF) that enhances CAF with weak constraints. Intuitively, these constraints can be used to find “optimal” solutions to problems defined through CAF. We provide a detailed complexity analysis of CAF and WAF, showing that strong constraints do not increase the expressive power of AF in most cases, while weak constraints systematically increase the expressive power of CAF (and AF) under several well-known argumentation semantics.

On generalized notions of consistency and reinstatement and their preservation in formal argumentation

We present a conceptualization providing an original domain-independent perspective on two crucial properties in reasoning: consistency and reinstatement. They emerge as a pair of dual characteristics, representing complementary requirements on the outcomes of reasoning processes. Central to our formalization are two underlying parametric relations: incompatibility and reinstatement violation. Different instances of these relations give rise to a spectrum of consistency and reinstatement scenarios. As a demonstration of versatility and expressive power of our approach we provide a characterization of various abstract argumentation semantics which are expressed as combinations of distinct consistency and reinstatement constraints. Moreover, we conduct an investigation into preserving these essential properties across different reasoning stages. Specifically, we delve into scenarios where a labelling is derived from other labellings through a synthesis function, using the synthesis of argument justification as an illustrative instance. We achieve a general characterization of consistency preservation synthesis functions, while we unveil an impossibility result concerning reinstatement preservation, leading us to explore an alternative notion to ensure feasibility. Our exploration reveals a weakness in the traditional definition of argument justification, for which we propose a refined version overcoming this limitation.

Metaethics and the Nature of Properties

Abstract This paper explores connections between theories of morality and theories of properties. It argues that (1) moral realism is in tension with predicate, class and mereological nominalism; (2) moral non-naturalism is incompatible with standard versions of resemblance nominalism, immanent realism and trope theory; and (3) the standard semantic arguments for property realism do not support moral realism. I also raise doubts about trope-theoretic explanations of moral supervenience and argue against one version of the principle that we should accept theories that maintain neutrality.

ω-Groundedness of argumentation and completeness of grounded dialectical proof procedures

Dialectical proof procedures in assumption-based argumentation are in general sound but not complete with respect to both the credulous and skeptical semantics (due to non-terminating loops). This raises the question of whether we could describe exactly what such procedures compute. In a previous paper, we introduce infinite arguments to represent possibly non-terminating computations and present dialectical proof procedures that are both sound and complete with respect to the credulous semantics of assumption-based argumentation with infinite arguments. In this paper, we study whether and under what conditions dialectical proof procedures are both sound and complete with respect to the grounded semantics of assumption-based argumentation with infinite arguments. We introduce the class of ω-grounded and finitary-defensible argumentation frameworks and show that finitary assumption-based argumentation is ω-grounded and finitary-defensible. We then present dialectical procedures that are sound and complete wrt finitary assumption-based argumentation.

Weighted knowledge bases with typicality and defeasible reasoning in a gradual argumentation semantics

Weighted knowledge bases for description logics with typicality provide a logical interpretation of MultiLayer Perceptrons, based on a “concept-wise” multi-preferential semantics. On the one hand, in the finitely many-valued case, Answer Set Programming (ASP) has been shown to be suitable for addressing defeasible reasoning from weighted knowledge bases for the boolean fragment of ALC . On the other hand, the semantics of weighted knowledge bases with typicality, in their different variants, have suggested some new gradual argumentation semantics, as well as an approach for defeasible reasoning over a weighted argumentation graph, building on the gradual semantics and, specifically on the φ-coherent semantics. In this paper, we explore the relationships between weighted knowledge bases and weighted argumentation graphs, to develop proof methods for defeasible reasoning over an argumentation graph under the φ-coherent semantics, in the finitely-valued case. We establish a mapping from a weighted argumentation graph to a weighted knowledge base as well as a lower bound on the complexity of the problem of verifying graded implications over an argumentation graph in the φ-coherent semantics. We also consider a mapping from weighted knowledge bases to weighted argumentation graphs, and provide an ASP implementation and some experimental results.

Reduced meet over labelling-based semantics in abstract argumentation

The labelling-based approach of abstract argumentation frameworks (AAFs) is beneficial for various applications requiring different levels of decisiveness. For labelling-based semantics, this paper provides an operator so-called reduced meet modulo an ultrafilter, which is inspired by its counterpart over extensions. All criteria involved in the definitions of fundamental labelling-based semantics in AAFs are shown to be closed under this operator. Based on this fact, this paper develops a simple and uniform way for exploring common properties of labelling-based semantics in AAFs, including the compactness of extensibility, the Dcpo and Lindenbaum properties, etc.

Attack principles in sequent-based argumentation theory

Abstract Attack principles have been introduced in semi-abstract argumentation frameworks and, in the present work, we interpret them in sequent-based argumentation frameworks. Thus, we investigate the role of minimality and consistency of the support set of an argument. Through the notion of preservation of strength, we introduce a formal criterion to sort out the attack principles; isolate the more “acceptable” ones, i.e. those easier to justify; and recover a new argumentative semantics for the non-classical logic that arises from dropping the rules $(\neg , r)$, $(\land , r)$ and $(\supset , l)$ from Gentzen’s classical sequent calculus for classical logic $\textsf{LK}$.

Neighborhood-based argumental community support in the context of multi-topic debates

The formal characterization of abstract argumentation has allowed the study of many exciting characteristics of the argumentation process. Nevertheless, while helpful in many aspects, abstraction diminishes the knowledge representation capabilities available to describe naturally occurring features of argumentative dialogues; one of these elements is the consideration of the topics involved in a discussion. In studying dialogical processes, participants recognize that some topics are closely related to the original issue; in contrast, others are more distant from the central subject or refer to unrelated matters. Consequently, it is reasonable to study different argumentation semantics that considers a discussion's focus to evaluate acceptability. In this work, we introduce the necessary representational elements required to reflect the focus of a discussion. We propose a novel extension of the semantics for multi-topic abstract argumentation frameworks, acknowledging that every argument has its own zone of relevance in the argumentation framework, leading to the concepts of neighborhoods and communities of legitimate defenses. Furthermore, other semantic elaborations are defined and discussed around this structure.

Necessary and sufficient conditions of the enforcement problem for various argumentation semantics

Abstract In the research on dynamics of argumentation frameworks (AFs), the enforcement problem deals with changing an AF for the purpose of ensuring that a certain set of desired arguments becomes (part of) an extension. In this paper we focus on expansions of an AF where solely the addition of new arguments and attacks is allowed and the original framework remains unchanged. Existing results about the enforcement problem are all sufficient conditions, and we argue that necessary and sufficient conditions are essential concerning the solvability of the enforcement problem. A suite of jointly necessary and sufficient conditions are identified for the enforcement problem under normal expansion. These conditions are presented from multiple perspectives including the sub-strict versus non-strict problem, constructive versus eliminative conditions and arbitrary AFs versus even(odd)-length cycle free AFs, determined by the nature of various argumentation semantics. Such necessary and sufficient conditions are of the essence to the enforcement problem by defining requirements that are both minimum and absolute, which can be used to determine when the enforcement problem is (un)solvable. We further infer solely sufficient and solely necessary conditions based on the partial order relation (w.r.t. set-inclusion) among various types of AF extensions.

Investigation of the Visual-Semantic Relations in Typography

The technological advancements initiated with the onset of the Industrial Revolution and persisting rapidly to this day continue to instigate profound transformations in societies, cultures, and even forms of governance, while simultaneously ushering in new perspectives and methodologies in the realms of art and design. In our age, the concept of language has ceased to be a mere means of communication and has adapted organically to the developing age by assuming certain missions and roles. These roles involve the articulation of narratives and meanings designed to integrate individuals into the existing capitalist system and manage their needs. This study examines the relationship between typography and language as a design element within the context of semantic arguments. The primary aim here is to analyze the semantic structures of typography as a design element, not only facilitating readability but also visibility, and to dissect them from a semantic standpoint, from parts to the whole. In doing so, it aims to uncover the effectiveness of typography as a tool for perception management. The presented data is anticipated to provide designers, particularly, with methods to enhance the use of typography in conveying messages, meanings, and relationships with the reader, thereby increasing efficiency in terms of conveying meaning and offering various approaches to enhance semantic productivity. The aim of this study is to position the semantic relationships between the meanings of typographic elements used in graphic design products and how viewers visually perceive the typography used. Thus, the exploration aims to discover how visually symbolic meanings created with typography can be utilized as a more effective form of communication.

Explanation–Question–Response dialogue: An argumentative tool for explainable AI

Advancements and deployments of AI-based systems, especially Deep Learning-driven generative language models, have accomplished impressive results over the past few years. Nevertheless, these remarkable achievements are intertwined with a related fear that such technologies might lead to a general relinquishing of our lives’s control to AIs. This concern, which also motivates the increasing interest in the eXplainable Artificial Intelligence (XAI) research field, is mostly caused by the opacity of the output of deep learning systems and the way that it is generated, which is largely obscure to laypeople. A dialectical interaction with such systems may enhance the users’ understanding and build a more robust trust towards AI. Commonly employed as specific formalisms for modelling intra-agent communications, dialogue games prove to be useful tools to rely upon when dealing with user’s explanation needs. The literature already offers some dialectical protocols that expressly handle explanations and their delivery. This paper fully formalises the novel Explanation–Question–Response (EQR) dialogue and its properties, whose main purpose is to provide satisfactory information (i.e., justified according to argumentative semantics) whilst ensuring a simplified protocol, in comparison with other existing approaches, for humans and artificial agents.

A Syntactic Proof of the Decidability of First-Order Monadic Logic

Decidability of monadic first-order classical logic was established by Löwenheim in 1915. The proof made use of a semantic argument and a purely syntactic proof has never been provided. In the present paper we introduce a syntactic proof of decidability of monadic first-order logic in innex normal form which exploits G3-style sequent calculi. In particular, we introduce a cut- and contraction-free calculus having a (complexity-optimal) terminating proof-search procedure. We also show that this logic can be faithfully embedded in the modal logic T.

Demystification and Actualisation of Data Saturation in Qualitative Research Through Thematic Analysis

The concept of saturation in qualitative research is a widely debated topic. Saturation refers to the point at which no new data or themes are emerging from the data set, which indicates that the data have been fully explored. It is considered an important concept as it helps to ensure that the findings are robust and that the data are being used to their full potential to achieve the research aim. Saturation, or the point at which further observation of data will not lead to the discovery of more information related to the research questions, is an important aspect of qualitative research. However, there is some mystification and semantic debate surrounding the term saturation, and it is not always clear how many rounds of research are needed to reach saturation or what criteria are used to make that determination during the thematic analysis process. This paper focuses on the actualisation of saturation in the context of thematic analysis and develops a systematic approach to using data to justify the contribution of research. Consequently, we introduce a distinct model to help researchers reach saturation through refining or expanding existing quotations, codes, themes and concepts as necessary.

VOICE SYSTEMS IN MANGGARAI: HOW SEMANTIC ROLES BEHAVE IN THE CLAUSES

This research evaluates Klamer's statement that says several languages in the Lesser Sunda Islands (and some languages in Sulawesi) do not have passive constructions. Therefore, this study aims to prove whether the Manggarai language has passive construction forms with different semantic roles. The data used in this study are clauses in the Manggarai language that contain five semantic role arguments: actor, patient, benefactive, instrumental, and locative. This is done by examining the semantic role argument to be positioned as the subject. The results show that the Manggarai language is indeed a language that has two voices, which means that active and passive constructions exist. However, Manggarai does not experience morphological changes in the verbs but is marked by the emergence of prepositions when changed into passive constructions. In the Kempo dialect of the Manggarai language, the preposition le ‘by’ not only introduces actors in passive constructions but also serves to introduce instrumental roles in active sentences. The preposition latang 'for' introduces a benefactive argument in both active and passive constructions. Preposition one ‘in/on’ serves to introduce a locative argument in active and passive clauses.

An empirical and axiomatic comparison of ranking-based semantics for abstract argumentation

Argumentation is the process of evaluating and comparing a set of arguments. A way to compare them consists in using a ranking-based semantics which rank-order arguments from the most to the least acceptable ones. Recently, a number of such semantics have been proposed independently, often associated with some desirable properties. In this work, we provide a thorough analysis of ranking-based semantics in two different ways. The first is an empirical comparison on randomly generated argumentation frameworks which reveals insights into similarities and differences between ranking-based semantics. The second is an axiomatic comparison of all these semantics with respect to the proposed properties aiming to better understand the behaviour of each semantics.

Semantic roles arguments verb in the kurdish language accordind to the model of van valin (2005 ad)

The semantics roles are considered one of the important linguistic topics. This research aims at shedding light on the semantic roles that Van Valin (2005 AD) has included, since his model is distinguished from other models of semantic roles, whether in terms of the number of semantic roles or in terms of naming each semantic role. This study has applied this model to the local dialect of Bahdin Kurdish, as it has showed verb arguments according to Van Valin model, because this semantic role is assigned to the argument. The most important questions that have been raised by this study: How many semantic roles are there according to (Van) Valin‌s model (2005 AD) In what case is the word an argument and in what case is it complementary? At the end, the relevant findings have been discussed in terms of Van Valin‌s (2005 AD) models. Moreover, the semantic roles have been divided into three levels, each level contains as aspect of the semantic roles, and it has been able to display 40 thematic relationships. The current study has succeeded to distinguish between arguments and compliments.

A claim-centric perspective on abstract argumentation semantics: Claim-defeat, principles, and expressiveness

Dung's abstract argumentation frameworks (AFs) are a key formalism in AI research nowadays. Claims are an inherent part of each argument; they substantially determine the structure of the abstract representation. Nevertheless, they are often not taken into account on the abstract level, which restricts the modeling capacities of AFs to problems that do not involve claims in the evaluation. In this work, we address this shortcoming and conduct a structural analysis of claim-based argumentation semantics utilizing claim-augmented argumentation frameworks (CAFs) which extend AFs by assigning a claim to each argument. Our main contributions are as follows: We first propose novel variants for preferred, naive, stable, semi-stable, and stage semantics based on claim-defeat and claim-set maximization, complementing existing CAF semantics. Among our findings is that for a certain subclass, namely well-formed CAFs, the different versions of preferred and stable semantics coincide, which is not the case for the other semantics. We then conduct a principle-based analysis of the semantics with respect to general and well-formed CAFs. Finally, we study the expressiveness of the semantics by characterizing their signatures. In summary, this paper provides a thorough analysis of fundamental properties of abstract argumentation semantics (along the lines of existing results for AFs) but from the perspective of the claims the arguments represent. This shift of perspective provides novel results which we deem relevant when abstract argumentation is used in an instantiation-based setting.

The robotic-surgery propositional bank

Robot-assisted minimally invasive surgery is the gold standard for the surgical treatment of many pathological conditions since it guarantees to the patient shorter hospital stay and quicker recovery. Several manuals and academic papers describe how to perform these interventions and thus contain important domain-specific knowledge. This information, if automatically extracted and processed, can be used to extract or summarize surgical practices or develop decision making systems that can help the surgeon or nurses to optimize the patient’s management before, during, and after the surgery by providing theoretical-based suggestions. However, general English natural language understanding algorithms have lower efficacy and coverage issues when applied to domain others than those they are typically trained on, and a domain specific textual annotated corpus is missing. To overcome this problem, we annotated the first robotic-surgery procedural corpus, with PropBank-style semantic labels. Starting from the original PropBank framebank, we enriched it by adding new lemmas, frames and semantic arguments required to cover missing information in general English but needed in procedural surgical language, releasing the Robotic-Surgery Procedural Framebank (RSPF). We then collected from robotic-surgery textbooks as-is sentences for a total of 32,448 tokens, and we annotated them with RSPF labels. We so obtained and publicly released the first annotated corpus of the robotic-surgical domain that can be used to foster further research on language understanding and procedural entities and relations extraction from clinical and surgical scientific literature.

Kettle logic in abstract argumentation

Abstract Kettle logic is a colloquial term that describes an agent’s advancement of inconsistent arguments in order to defeat a particular claim. Intuitively, a consistent subset of the advanced arguments should exist that is at least as successful at refuting the claim as the advancement of the set of inconsistent arguments. In this paper, we formalize this intuition and provide a formal analysis of kettle logic in abstract argumentation, a fundamental approach to computational argumentation, showing that all of the analysed abstract argumentation semantics (inference functions)—with the exception of naive semantics, which is considered a mere simplistic helper for the construction of other semantics—suffer from kettle logic. We also provide an approach to mitigating kettle logic under some circumstances. The key findings presented in this paper highlight that agents that apply the inference functions of abstract argumentation, are—similarly to humans—receptive to persuasion by agents who deliberately advance inconsistent and intuitively ‘illogical’ claims. As abstract argumentation can be considered one of the most basic models of computational argumentation, this raises the question to what extent and under what circumstances kettle logic-free argumentation can and should be enforced by computational means.

Evaluating and selecting arguments in the context of higher order uncertainty.

Human and artificial reasoning has to deal with uncertain environments. Ideally, probabilistic information is available. However, sometimes probabilistic information may not be precise or it is missing entirely. In such cases we reason with higher-order uncertainty. Formal argumentation is one of the leading formal methods to model defeasible reasoning in artificial intelligence, in particular in the tradition of Dung's abstract argumentation. Also from the perspective of cognition, reasoning has been considered as argumentative and social in nature, for instance by Mercier and Sperber. In this paper we use formal argumentation to provide a framework for reasoning with higher-order uncertainty. Our approach builds strongly on Haenni's system of probabilistic argumentation, but enhances it in several ways. First, we integrate it with deductive argumentation, both in terms of the representation of arguments and attacks, and in terms of utilizing abstract argumentation semantics for selecting some out of a set of possibly conflicting arguments. We show how our system can be adjusted to perform well under the so-called rationality postulates of formal argumentation. Second, we provide several notions of argument strength which are studied both meta-theoretically and empirically. In this way the paper contributes a formal model of reasoning with higher-order uncertainty with possible applications in artificial intelligence and human cognition.