Logic at GU

Welcome to the webpage of the logic group at the University of Gothenburg. Information about our research and activities can be found through the links to the left. More detailed information is available through the personal pages of group members and our homepage at the University of Gothenburg.

Upcoming seminars

Past talks can be found on the seminar page. Announcements of upcoming seminars and events are distributed via the seminar mailing list.

Dag Westerståhl (Stockholm University and Tsinghua University, Beijing) Carnap’s problem for intuitionistic propositional logic

I will first give a brief background, with some examples, on ‘Carnap’s problem’: to what extent a consequence relation in a formal language fixes the meaning, relative to some given semantics, of the logical constants in that language. I then focus on intuitionistic propositional logic and show that it is ‘Carnap categorical’: the only interpretation of the connectives consistent with the usual intuitionistic consequence relation is the standard one. This holds relative to most well-known semantics with respect to which intuitionistic logic is sound and complete; among them Kripke semantics, Beth semantics, Dragalin semantics, and topological semantics. It also holds for algebraic semantics, although categoricity in that case is different in kind from categoricity relative to possible worlds style semantics. This is joint work with Haotian Tong.

Julseminarium To Be Announced

Nordic Online Logic Seminar

Alexandru Baltag (University of Amsterdam) From Surprise Exams to Topological Mu-Calculus

I present a topological epistemic logic, motivated by a famous epistemic puzzle: the Surprise Exam Paradox. It is a fixed-point modal logic, with modalities for knowledge (modelled as the universal modality), knowability of a proposition (represented by the topological interior operator), and (un)knowability of the actual world. The last notion has a non-self-referential reading (modelled by Cantor derivative: the set of limit points of a given set) and a self-referential one (modelled by the so-called perfect core of a given set: its largest subset which is a fixed point of relativized derivative). I completely axiomatize this logic, showing that it is decidable and PSPACE-complete, as well as briefly explain how the same model-theoretic method can be elaborated to prove the completeness and decidability of the full topological mu-calculus. Finally, I apply it to the analysis of the Surprise Exam Paradox and other puzzles.

(… read full abstract …)

This talk is part of the Nordic Online Logic Seminar Series.

Licentiate defence: Giacomo Barlucchi (FLoV) Computational content of fixed points

Public defence of Giacomo Barlucchi’s Licentiate thesis.

Examiner Docent Fredrik Engström, Göteborgs universitet
Opponent Docent Sebastian Enqvist, Stockholms universitet

(… read full abstract …)

Logic Seminar

Logic Seminar

Logic Seminar

Logic Seminar

Logic Seminar

Logic Seminar

Logic Seminar

Logic Seminar

Logic Seminar

Logic Seminar