Hannes Strass’s research while affiliated with TU Dresden and other places

... Declarative rule languages are central to knowledge representation and reasoning (KRR), be it as the foundation of logic programming (Körner et al. 2022;Calimeri et al. 2020), as a design principle for ontology languages (ter Horst 2005; Motik et al. 2009;Krötzsch, Rudolph, and Hitzler 2013), or merely as a computational framework for reasoning (Gómez Álvarez, Rudolph, and Strass 2023;Simančík, Kazakov, and Horrocks 2011;Krötzsch 2011). Indeed, few logical paradigms embody such harmony of intuitive meaning, formal semantics, and practical execution. ...

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Nemo: Your Friendly and Versatile Rule Reasoning Toolkit

... Despite the PTIME translation, it remains to be seen if this approach performs well in practical cases. An alternative would be to devise a quasimodel-based tableau algorithm along the lines of (Wolter and Zakharyaschev 1998;Gómez Álvarez, Rudolph, and Strass 2023b), yet this would be a challenging endeavour since it requires the implementation of a tailored reasoner. ...

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Reasoning in SHIQ with Axiom- and Concept-Level Standpoint Modalities

... In contrast to our work, those views limit the model to certain aspects that are relevant in it but do not modify the underlying facts or assumptions based on the view taken. More similar to our work are approaches of ontology integration [42] and specialized description logics allowing for reasoning with different ontology vocabularies (e.g., [43,44,45]). The difference of those works to our approach is that information fusion in our model seeks sufficient agreement between different viewpoints, in order to aggregate knowledge graphs representing the different viewpoints. ...

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A Conceptual Model for Attributions in Event-Centric Knowledge Graphs

... In the case of bipolarity of ADFs, the focus is on attacking and supporting relations between arguments, which are represented by bipolar acceptance conditions. Bipolar ADFs were first introduced by [18], and have been investigated to quite some depth later on regarding complexity issues [18,69], relations to other argumentation formalisms [61], number of bipolar acceptance conditions [7], importing ideas of bipolarity of ADFs to logic programming [4], studying expressivity of bipolar ADFs [51,66], and bipolarity was used in investigations of admissibility [62]. More generally, bipolarity in formal argumentation has, likewise, received attention from the community [21]. ...

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Advanced Algorithms for Abstract Dialectical Frameworks based on Complexity Analysis of Subclasses and SAT Solving

... The additional expressive power is achieved by adding acceptance conditions to the arguments which allow for the specification of more complex relationships between them. Of particular interest might be the subclass of bipolar ADFs (BADFs) which are as complex as AFs while arguably offering more modelling capabilities (Brewka, Ellmauthaler, Strass, Wallner, & Woltran, 2017;Straß & Wallner, 2015;Baumann & Heinrich, 2023). It is one highly relevant future task to investigate notions of forgetting in these more expressive argumentation formalisms. ...

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Forgetting in Abstract Argumentation: Limits and Possibilities

... Now let us turn to strong equivalence [25,13], i.e. how to decide whether two AFs are interchangeable in any given context without changing the semantics. More formally, in case of a labelling-based semantics L σ , two AFs F and G are strongly equivalent (denoted as F ≡ Lσ s G) if and only if L σ (F ⊔ H ) = L σ (G ⊔ H ) for any further AF H . ...

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On Naive Labellings – Realizability, Construction and Patterns of Redundancy

... Conditional independence has been investigated in several other logic-based frameworks, such as (iterated) belief revision (Lynn, Delgrande, and Peppas, 2022;Kern-Isberner, Heyninck, and Beierle, 2022), conditional logics (Heyninck, Kern-Isberner, and Meyer, 2022) and formal argumentation (Rienstra et al., 2020;Gaggl, Rudolph, and Strass, 2021). The benefit of our work is that the algebraic nature allows for the straightforward application to other formalisms with a fixpoint semantics. ...

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An Algebraic Notion of Conditional Independence, and Its Application to Knowledge Representation (full version)

... One approach to reasoning in ASPIC + consists of first explicitly constructing arguments from these building blocks, which gives rise to a corresponding abstract argumentation framework (Modgil and Prakken 2013), and then reasoning over the abstract argumentation framework in order to decide whether the conclusions of interest can be drawn (Dung 1995). However, this two-step approach is cumbersome in both theory and practice (Lehtonen, Wallner, and Järvisalo 2020) as the first step of argument construction may give rise to an exponentially larger abstract framework (Strass, Wyner, and Diller 2019). This makes it challenging to establish complexity results for ASPIC + reasoning and to develop practical algorithms. ...

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Complexity Results and Algorithms for Preferential Argumentative Reasoning in ASPIC+

... That is, we may view φ as an independent module of Φ. Within the KR community it is folklore that this is usually not the case for non-monotonic logics (apart from folklore, we refer the reader to (Baumann and Strass 2016) for a rigorous study of this matter). ...

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Equivalence in Argumentation Frameworks with a Claim-Centric View – Classical Results with Novel Ingredients

... However, by definition of Boolean network, the acceptance condition of an argument depends on all the parents of that argument. Hence, contingency (11) To see this, assume that φ b depends on a, and observe that φ b is not anti-monotone on a The fact that we can transit from monotonicity to derivation through negation suggests considering strict interactions (used, for instance, in [16]) so that strict monotonicity is equivalent to the strictly positive derivative. We thus get: ...

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Bridging abstract dialectical argumentation and Boolean gene regulation