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Journal articleDickie C, Lauren S, Belardinelli F, et al., 2025,
Aggregating bipolar opinions through bipolar assumption-based argumentation
, Autonomous Agents and Multi-Agent Systems, Vol: 39, ISSN: 1387-2532We introduce a novel method to aggregate Bipolar ArgumentationFrameworks expressing opinions of different parties in debates. We use BipolarAssumption-based Argumentation (ABA) as an all-encompassing formalismfor Bipolar Argumentation under different semantics. By leveraging on recentresults on judgement aggregation in Social Choice Theory, we prove severalpreservation results for relevant properties of Bipolar ABA using quota andoligarchic rules. Specifically, we prove (positive and negative) results about thepreservation of conflict-free, closed, admissible, preferred, complete, set-stable,well-founded and ideal extensions in Bipolar ABA, as well as the preservationof acceptability, acyclicity and coherence for individual assumptions. Finally,we illustrate our methodology and results in the context of a case study onopinion aggregation for the treatment of long COVID patients.
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Conference paperThomas D, Jiang J, Kori A, et al., 2024,
Explainable reinforcement learning for Formula One race strategy
, The 40th ACM/SIGAPP Symposium On Applied Computing, Publisher: ACMIn Formula One, teams compete to develop their cars to achieve the highest possible finishing position in each race. During a race, however, teams are unable to alter the car, so they must improve their cars’ finishing positions via race strategy, i.e. optimising their selection of which tyre compounds to put on the car and when to do so. In this work, we introduce a reinforcement learning model, RSRL(Race Strategy Reinforcement Learning), to control race strategies in simulations, offering a faster alternative to the industry standard of hard-coded and Monte Carlo-based race strategies. Controlling cars with a pace equating to an expected finishing position of P5.5 (where P1 represents first place and P20 is last place), RSRL achieves an average finishing position of P5.33 on our test race, the 2023Bahrain Grand Prix, outperforming the best baseline of P5.63. We then demonstrate, in a generalisability study, how performance for one track or multiple tracks can be prioritised via training. Further, we supplement model predictions with feature importance, decision tree-based surrogate models, and decision tree counterfactualstowards improving user trust in the model. Finally, we provide illustrations which exemplify our approach in real-world situations, drawing parallels between simulations and reality.
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Conference paperTodd J, Jiang J, Russo A, et al., 2024,
Explainable time series prediction of tyre energy in formula one race strategy
, SAC 2025: The 40th ACM/SIGAPP Symposium On Applied Computing, Publisher: ACMFormula One (F1) race strategy takes place in a high-pressure and fast-paced environment where split-second decisions can drastically affect race results. Two of the core decisions of race strategy are when to make pit stops (i.e. replace the cars’ tyres) and which tyre compounds (hard, medium or soft, in normal conditions) to select. The optimal pit stop decisions can be determined by estimatingthe tyre degradation of these compounds, which in turn can be computed from the energy applied to each tyre, i.e. the tyre energy. In this work, we trained deep learning models, using an F1 team’s historic race data consisting of telemetry, to forecast tyre energies during races. Additionally, we fitted XGBoost, a decision tree-based machine learning algorithm, to the same dataset and compared the results, with both giving impressive performance. Furthermore, weincorporated two different explainable AI methods, namely feature importance and counterfactual explanations, to gain insights into the reasoning behind the forecasts. Our contributions thus result in an explainable, automated method which could assist F1 teams in optimising their race strategy.
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Conference paperRapberger A, Ulbricht M, Toni F, 2024,
On the correspondence of non-flat assumption-based argumentation and logic programming with negation as failure in the head
, 22nd International Workshop on Nonmonotonic Reasoning NMR 24), Publisher: CEUR Workshop Proceedings, Pages: 122-121, ISSN: 1613-0073The relation between (a fragment of) assumption-based argumentation (ABA) and logic programs (LPs) under stable model semantics is well-studied. However, for obtaining this relation, the ABA framework needs to be restricted to being flat, i.e., a fragment where the (defeasible) assumptions can never be entailed, only assumed to be true or false. Here, we remove this restriction and show a correspondence between non-flat ABA and LPs with negation as failure in their head. We then extend this result to so-called set-stable ABA semantics, originally defined for the fragment of non-flat ABA called bipolar ABA. We showcase how to define set-stable semantics for LPs with negation as failure in their head and show the correspondence to set-stable ABA semantics.
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Conference paperVasileiou S, Kumar A, Yeoh W, et al., 2024,
Dialectical reconciliation via structured argumentative dialogues
, KR 2024We present a novel framework designed to extend model reconciliation approaches, commonly used in human-aware planning, for enhanced human-AI interaction. By adopting a structured argumentation-based dialogue paradigm, our framework enables dialectical reconciliation to address knowledge discrepancies between an explainer (AI agent) and an explainee (human user), where the goal is for the explainee to understand the explainer's decision. We formally describe the operational semantics of our proposed framework, providing theoretical guarantees. We then evaluate the framework's efficacy ``in the wild'' via computational and human-subject experiments. Our findings suggest that our framework offers a promising direction for fostering effective human-AI interactions in domains where explainability is important.
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Conference paperBattaglia E, Baroni P, Rago A, et al., 2024,
Integrating user preferences into gradual bipolar argumentation for personalised decision support
, Scalable Uncertainty Management, 16th International Conference (SUM 2024), Publisher: Springer, Pages: 14-28, ISSN: 1611-3349Gradual bipolar argumentation has been shown to be aneffective means for supporting decisions across a number of domains. Individual user preferences can be integrated into the domain knowledge represented by such argumentation frameworks and should be taken into account in order to provide personalised decision support. This howeverrequires the definition of a suitable method to handle user-provided preferences in gradual bipolar argumentation, which has not been considered in previous literature. Towards filling this gap, we develop a conceptual analysis on the role of preferences in argumentation and investigate some basic principles concerning the effects they should have on the evaluation of strength in gradual argumentation semantics. We illustrate an application of our approach in the context of a review aggregation system, which has been enhanced with the ability to produce personalisedoutcomes based on user preferences.
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Conference paperRago A, Vasileiou SL, Toni F, et al., 2024,
A Methodology for Gradual Semantics for Structured Argumentation under Incomplete Information
, ArXiv -
Journal articleKampik T, Potyka N, Yin X, et al., 2024,
Contribution functions for quantitative bipolar argumentation graphs: a principle-based analysis
, International Journal of Approximate Reasoning, Vol: 173, ISSN: 0888-613XWe present a principle-based analysis of contribution functions for quantitative bipolar argumentation graphs that quantify the contribution of one argument to another. The introduced principles formalise the intuitions underlying different contribution functions as well as expectations one would have regarding the behaviour of contribution functions in general. As none of the covered contribution functions satisfies all principles, our analysis can serve as a tool that enables the selection of the most suitable function based on the requirements of a given use case.
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Conference paperRapberger A, Toni F, 2024,
On the robustness of argumentative explanations
, 10th International Conference on Computational Models of Argument (COMMA 2024), Publisher: IOS Press, Inc., Pages: 217-228The field of explainable AI has grown exponentially in recent years.Within this landscape, argumentation frameworks have shown to be helpful ab-stractions of some AI models towards providing explanations thereof. While exist-ing work on argumentative explanations and their properties has focused on staticsettings, we focus on dynamic settings whereby the (AI models underpinning the)argumentation frameworks need to change. Specifically, for a number of notionsof explanations drawn from abstract argumentation frameworks under extension-based semantics, we address the following questions: (1) Are explanations robust toextension-preserving changes, in the sense that they are still valid when the changesdo not modify the extensions? (2) If not, are these explanations pseudo-robust inthat can be tractably updated? In this paper, we frame these questions formally. Weconsider robustness and pseudo-robustness w.r.t. ordinary and strong equivalenceand provide several results for various extension-based semantics.
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Conference paperLehtonen T, Rapberger A, Toni F, et al., 2024,
On computing admissibility in ABA
, 10th International Conference on Computational Models of Argument (COMMA 2024), Publisher: IOS Press, Inc., Pages: 121-132Most existing computational tools for assumption-based argumentation (ABA) focus on so-called flat frameworks, disregarding the more general case. Here, we study an instantiation-based approach for reasoning in possibly non-flat ABA. For complete-based semantics, an approach of this kind was recently introduced, based on a semantics-preserving translation between ABA and bipolar argumentation frameworks (BAFs). Admissible semantics, however, require us to consider an extension of BAFs which also makes use of premises of arguments (pBAFs).We explore basic properties of pBAFs which we require as a theoretical underpinning for our proposed instantiation-based solver for non-flat ABA under admissible semantics. As our empirical evaluation shows, depending on the ABA instances, the instantiation-based solver is competitive against an ASP-based approach implemented in the style of state-of-the-art solvers for hard argumentation problems.
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Conference paperAyoobi H, Potyka N, Toni F, 2024,
Argumentative interpretable image classification
, 2nd International Workshop on Argumentation for eXplainable AI co-located with the 10th International Conference on Computational Models of Argument (COMMA 2024), Publisher: CEUR Workshop Proceedings, Pages: 3-15, ISSN: 1613-0073We propose ProtoSpArX, a novel interpretable deep neural architecture for image classification in the spirit of prototypical-part-learning as found, e.g. in ProtoPNet. While earlier approaches associate every class with multiple prototypical-parts, ProtoSpArX uses super-prototypes that combine prototypical-parts into single class representations. Furthermore, while earlier approaches use interpretable classification layers, e.g. logistic regression in ProtoPNet, ProtoSpArX improves accuracy with multi-layer perceptronswhile relying upon an interpretable reading thereof based on a form of argumentation. ProtoSpArX is customisable to user cognitive requirements by a process of sparsification of the multi-layer perceptron/argumentation component. Also, as opposed to other prototypical-part-learning approaches,ProtoSpArX can recognise spatial relations between different prototypical-parts that are from various regions in images, similar to how CNNs capture relations between patterns recognized in earlier layers.
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Conference paperSukpanichnant P, Rapberger A, Toni F, 2024,
PeerArg: argumentative peer review with LLMs
, First International Workshop on Next-Generation Language Models for Knowledge Representation and Reasoning (NeLaMKRR 2024)Peer review is an essential process to determine the quality of papers submitted to scientific conferences or journals. However, it is subjective and prone to biases. Several studies have been conducted to apply techniques from NLP to support peer review, but they are based on black-box techniques and their outputs are difficult to interpret and trust. In this paper, we propose a novel pipeline to support and understand the reviewing and decision-making processes of peer review: the PeerArg system combining LLMs with methods from knowledge representation. PeerArg takes in input a set of reviews for a paper and outputs the paper acceptance prediction. We evaluate the performance of the PeerArg pipeline on three different datasets, in comparison with a novel end-2-end LLM that uses few-shot learning to predict paper acceptance given reviews. The results indicate that the end-2-end LLM is capable of predicting paper acceptance from reviews, but a variantof the PeerArg pipeline outperforms this LLM.
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Conference paperOluokun B, Paulino Passos G, Rago A, et al., 2024,
Predicting Human Judgement in Online Debates with Argumentation
, The 24th International Workshop on Computational Models of Natural Argument (CMNA’24) -
Conference paperYin X, Potyka N, Toni F, 2024,
Applying attribution explanations in truth-discovery quantitative bipolar argumentation frameworks
, 2nd International Workshop on Argumentation for eXplainable AI (ArgXAI) co-located with 10th International Conference on Computational Models of Argument (COMMA 2024), Publisher: CEUR Workshop Proceedings, ISSN: 1613-0073 -
Conference paperYin X, Potyka N, Toni F, 2024,
Explaining arguments’ strength: unveiling the role of attacks and supports
, IJCAI 2024, the 33rd International Joint Conference on Artificial Intelligence, Publisher: International Joint Conferences on Artificial Intelligence, Pages: 3622-3630Quantitatively explaining the strength of arguments under gradual semantics has recently received increasing attention. Specifically, several works in the literature provide quantitative explanations by computing the attribution scores of arguments. These works disregard the importance of attacks and supports, even though they play an essential role when explaining arguments' strength. In this paper, we propose a novel theory of Relation Attribution Explanations (RAEs), adapting Shapley values from game theory to offer fine-grained insights into the role of attacks and supports in quantitative bipolar argumentation towards obtaining the arguments' strength. We show that RAEs satisfy several desirable properties. We also propose a probabilistic algorithm to approximate RAEs efficiently. Finally, we show the application value of RAEs in fraud detection and large language models case studies.
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Conference paperFreedman G, Toni F, 2024,
Detecting scientific fraud using argument mining
, ArgMining@ACL2024, Publisher: Association for Computational Linguistics, Pages: 15-28proliferation of fraudulent scientific research in recent years has precipitated a greater interest in more effective methods of detection. There are many varieties of academic fraud, but a particularly challenging type to detect is the use of paper mills and the faking of peer-review. To the best of our knowledge, there have so far been no attempts to automate this process.The complexity of this issue precludes the use of heuristic methods, like pattern-matching techniques, which are employed for other types of fraud. Our proposed method in this paper uses techniques from the Computational Argumentation literature (i.e. argument mining and argument quality evaluation). Our central hypothesis stems from the assumption that articles that have not been subject to the proper level of scrutiny will contain poorly formed and reasoned arguments, relative to legitimately published papers. We use a variety of corpora to test this approach, including a collection of abstracts taken from retracted papers. We show significant improvement compared to a number of baselines, suggesting that this approach merits further investigation.
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Conference paperRusso F, Rapberger A, Toni F, 2024,
Argumentative Causal Discovery
, The 21st International Conference on Knowledge Representation and Reasoning (KR-2024) -
Conference paperLeofante F, Ayoobi H, Dejl A, et al., 2024,
Contestable AI needs Computational Argumentation
, KR 2024, Publisher: KR OrganizationAI has become pervasive in recent years, but state-of-the-art approaches predominantly neglect the need for AI systems to be contestable. Instead, contestability is advocated by AI guidelines (e.g. by the OECD) and regulation of automated decision-making (e.g. GDPR). In this position paper we explore how contestability can be achieved computationally in and for AI. We argue that contestable AI requires dynamic (human-machine and/or machine-machine) explainability and decision-making processes, whereby machines can (i) interact with humans and/or other machines to progressively explain their outputs and/or their reasoning as well as assess grounds for contestation provided by these humans and/or other machines, and (ii) revise their decision-making processes to redress any issues successfully raised during contestation. Given that much of the current AI landscape is tailored to static AIs, the need to accommodate contestability will require a radical rethinking, that, we argue, computational argumentation is ideally suited to support.
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Conference paperGould A, Paulino Passos G, Dadhania S, et al., 2024,
Preference-Based Abstract Argumentation for Case-Based Reasoning
, International Conference on Principles of Knowledge Representation and ReasoningIn the pursuit of enhancing the efficacy and flexibility of interpretable, data-driven classification models, this work introduces a novel incorporation of user-defined preferences with Abstract Argumentation and Case-Based Reasoning (CBR). Specifically, we introduce Preference-Based Abstract Argumentation for Case-Based Reasoning (which we call AA-CBR-P), allowing users to define multiple approaches to compare cases with an ordering that specifies their preference over these comparison approaches. We prove that the model inherently follows these preferences when making predictions and show that previous abstract argumentation for case-based reasoning approaches are insufficient at expressing preferences over constituents of an argument. We then demonstrate how this can be applied to a real-world medical dataset sourced from a clinical trial evaluating differing assessment methods of patients with a primary brain tumour. We show empirically that our approach outperforms other interpretable machine learning models on this dataset.
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Conference paperYin X, Potyka N, Toni F, 2024,
CE-QArg: Counterfactual explanations for quantitative bipolar argumentation frameworks
, 21st International Conference on Principles of Knowledge Representation and Reasoning, Publisher: International Joint Conferences on Artificial Intelligence OrganizationThere is a growing interest in understanding arguments’strength in Quantitative Bipolar Argumentation Frameworks(QBAFs). Most existing studies focus on attribution-basedmethods that explain an argument’s strength by assigning importance scores to other arguments but fail to explain how to change the current strength to a desired one. To solve this issue, we introduce counterfactual explanations for QBAFs. We discuss problem variants and propose an iterative algorithm named Counterfactual Explanations for Quantitative bipolar Argumentation frameworks (CE-QArg). CE-QArg can identify valid and cost-effective counterfactual explanations based on two core modules, polarity and priority, which help determine the updating direction and magnitude for each argument, respectively. We discuss some formal properties of our counterfactual explanations and empirically evaluate CE-QArg on randomly generated QBAFs.
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Conference paperMarzari L, Leofante F, Cicalese F, et al., 2024,
Rigorous probabilistic guarantees for robust counterfactual explanations
, 27th European Conference on Artificial Intelligence (ECAI 2024), Publisher: IOS PressWe study the problem of assessing the robustness ofcounterfactual explanations for deep learning models. We focus on plausible model shifts altering model parameters and propose a novel framework to reason about the robustness property in this setting. To motivate our solution, we begin by showing for the first time that computing the robustness of counterfactuals with respect to plausiblemodel shifts is NP-complete. As this (practically) rules out the existence of scalable algorithms for exactly computing robustness, we propose a novel probabilistic approach which is able to provide tight estimates of robustness with strong guarantees while preserving scalability. Remarkably, and differently from existing solutions targetingplausible model shifts, our approach does not impose requirements on the network to be analyzed, thus enabling robustness analysis on a wider range of architectures. Experiments on four binary classification datasets indicate that our method improves the state of the art ingenerating robust explanations, outperforming existing methods on a range of metrics.
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Conference paperProietti M, Toni F, De Angelis E, 2024,
Learning Brave Assumption-Based Argumentation Frameworks via ASP
, ECAI -
Conference paperVasileiou SL, Kumar A, Yeoh W, et al., 2024,
DR-HAI: argumentation-based dialectical reconciliation in human-AI interactions
, IJCAI 2023In this paper, we introduce DR-HAI – a novelargumentation-based framework designed to extend model reconciliation approaches, commonlyused in explainable AI planning, for enhancedhuman-AI interaction. By adopting a multi-shotreconciliation paradigm and not assuming a-prioriknowledge of the human user’s model, DR-HAI enables interactive reconciliation to address knowledge discrepancies between an explainer and an explainee. We formally describe the operational semantics of DR-HAI, and provide theoretical guarantees related to termination and success
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Conference paperJiang J, Rago A, Leofante F, et al., 2024,
Recourse under model multiplicity via argumentative ensembling
, The 23rd International Conference on Autonomous Agents and Multi-Agent Systems, Publisher: ACM, Pages: 954-963Model Multiplicity (MM) arises when multiple, equally performing machine learning models can be trained to solve the same prediction task. Recent studies show that models obtained under MM may produce inconsistent predictions for the same input. When this occurs, it becomes challenging to provide counterfactual explanations(CEs), a common means for offering recourse recommendations to individuals negatively affected by models’ predictions. In this paper, we formalise this problem, which we name recourse-aware ensembling, and identify several desirable properties which methods for solving it should satisfy. We demonstrate that existing ensemblingmethods, naturally extended in different ways to provide CEs, fail to satisfy these properties. We then introduce argumentative ensembling, deploying computational argumentation as a means to guarantee robustness of CEs to MM, while also accommodating customisable user preferences. We show theoretically and experimentally that argumentative ensembling is able to satisfy propertieswhich the existing methods lack, and that the trade-offs are minimal wrt the ensemble’s accuracy.
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Conference paperJiang J, Leofante F, Rago A, et al., 2024,
Robust Counterfactual Explanations in Machine Learning: A Survey
, The 33rd International Joint Conference on Artificial Intelligence, IJCAI 2024 -
Journal articleDomínguez J, Prociuk D, Marović B, et al., 2024,
ROAD2H: development and evaluation of an open-sourceexplainable artificial intelligence approach for managingco-morbidity and clinical guidelines
, Learning Health Systems, Vol: 8, ISSN: 2379-6146IntroductionClinical decision support (CDS) systems (CDSSs) that integrate clinical guidelines need to reflect real-world co-morbidity. In patient-specific clinical contexts, transparent recommendations that allow for contraindications and other conflicts arising from co-morbidity are a requirement. In this work, we develop and evaluate a non-proprietary, standards-based approach to the deployment of computable guidelines with explainable argumentation, integrated with a commercial electronic health record (EHR) system in Serbia, a middle-income country in West Balkans.MethodsWe used an ontological framework, the Transition-based Medical Recommendation (TMR) model, to represent, and reason about, guideline concepts, and chose the 2017 International global initiative for chronic obstructive lung disease (GOLD) guideline and a Serbian hospital as the deployment and evaluation site, respectively. To mitigate potential guideline conflicts, we used a TMR-based implementation of the Assumptions-Based Argumentation framework extended with preferences and Goals (ABA+G). Remote EHR integration of computable guidelines was via a microservice architecture based on HL7 FHIR and CDS Hooks. A prototype integration was developed to manage chronic obstructive pulmonary disease (COPD) with comorbid cardiovascular or chronic kidney diseases, and a mixed-methods evaluation was conducted with 20 simulated cases and five pulmonologists.ResultsPulmonologists agreed 97% of the time with the GOLD-based COPD symptom severity assessment assigned to each patient by the CDSS, and 98% of the time with one of the proposed COPD care plans. Comments were favourable on the principles of explainable argumentation; inclusion of additional co-morbidities was suggested in the future along with customisation of the level of explanation with expertise.ConclusionAn ontological model provided a flexible means of providing argumentation and explainable artificial intelligence for a long-term condition. Exte
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Conference paperLeofante F, Potyka N, 2024,
Promoting Counterfactual Robustness through Diversity
, The Thirty-Eighth AAAI Conference on Artificial Intelligence (AAAI24) -
Conference paperZhang D, Williams M, Toni F, 2024,
Targeted activation penalties help CNNs ignore spurious signals
, The 38th Annual AAAI Conference on Artificial Intelligence, Publisher: AAAI, ISSN: 2159-5399Neural networks (NNs) can learn to rely on spurious signals in the training data, leading to poor generalisation. Recent methods tackle this problem by training NNs with additional ground-truth annotations of such signals. These methods may, however, let spurious signals re-emerge in deep convolutional NNs (CNNs). We propose Targeted Activation Penalty (TAP), a new method tackling the same problem by penalising activations to control the re-emergence of spurious signals in deep CNNs, while also lowering training times and memory usage. In addition, ground-truth annotations can be expensive to obtain. We show that TAP still works well with annotations generated by pre-trained models as effective substitutes of ground-truth annotations. We demonstrate the power of TAP against two state-of-the-art baselines on the MNIST benchmark and on two clinical image datasets, using four different CNN architectures.
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Conference paperUlbricht M, Potyka N, Rapberger A, et al., 2024,
Non-flat ABA is an instance of bipolar argumentation
, The 38th Annual AAAI Conference on Artificial Intelligence, Publisher: AAAI, Pages: 10723-10731, ISSN: 2374-3468Assumption-based Argumentation (ABA) is a well-knownstructured argumentation formalism, whereby arguments and attacks between them are drawn from rules, defeasible assumptions and their contraries. A common restriction im-posed on ABA frameworks (ABAFs) is that they are flat, i.e.,each of the defeasible assumptions can only be assumed, but not derived. While it is known that flat ABAFs can be translated into abstract argumentation frameworks (AFs) as pro-posed by Dung, no translation exists from general, possibly non-flat ABAFs into any kind of abstract argumentation formalism. In this paper, we close this gap and show that bipolar AFs (BAFs) can instantiate general ABAFs. To this end we develop suitable, novel BAF semantics which borrow from the notion of deductive support. We investigate basic properties of our BAFs, including computational complexity, and prove the desired relation to ABAFs under several semantics.
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Conference paperKori A, Locatello F, De Sousa Ribeiro F, et al., 2024,
Grounded Object-Centric Learning
, International Conference on Learning Representations (ICLR)
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