时间: 5月7日 15:10-18:00

地点: 文史楼101  

TALK 1: Pooling Modalities and Pointwise Intersection: a Survey of Recent Results. 

Speakers: Dominik Klein, Postdoctoral Researcher at the University of Bamberg and the University of Bayreuth

                 Frederik Van De Putte, MSCA Fellow at the University of Bayreuth and Post-doctoral Fellow of the Flemish Research Foundation

                 (FWO-Vlaanderen) at Ghent University

Abstract: We study the enrichment of classical modal logics (in the sense of Chellas' seminal 1980 book) with pooling modalities, i.e. unary modal operators that allow one to express properties of sets obtained by the pointwise intersection of neighbourhood sets. In the first part, we discuss salient properties of these modalities, situate the logics in the broader area of modal logics (with a particular focus on relational semantics), establish key properties concerning their expressive power, and discuss their application to epistemic/doxastic logic, the logic of evidence-based belief, deontic logic, and logics of agency and ability. In the second, more technical part of the presentation, we show how completeness and the finite model property can be established for a number of logics with pooling modalities, using a novel technique in constructing canonical models.

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TALK 2: The Logic of Collective Acceptance 

Speaker: Frederik Van De Putte, MSCA Fellow at the University of Bayreuth and Post-doctoral Fellow of the Flemish Research Foundation (FWO-

               Vlaanderen) at Ghent University

Abstract: We present a logic that features three types of modalities: classical modal operators that express the norms endorsed by a given agent i; normal modalities that express what is required for the group G in view of the norms that are commonly endorsed by all its members; and normal modalities, that express what is required for an option to be universally acceptable within G. Although our semantics is relatively simple, it poses some challenges where axiomatization is concerned. We argue that this logic is useful as a stepping stone towards richer semantics that can express various types of collective acceptance and social norms.