Location

Institute of informatics
Neubrückstrasse 10
3012 Bern
+41 31 684 84 26
3rd floor, room 302.

Schedule

10:00 am - 12:00 am
Bahareh Afshari: "Cyclic Proof Theory"

Abstract: Proofs are a central tool in mathematics and a core concept in the study of formal reasoning. Traditionally, a proof is conceived as a finite object which is used to certify the correctness of our mathematical structures and their properties. Less common are so called cyclic proofs which, although infinitary, exhibit periodic patterns. Cyclic proof systems have proven to be a remarkably useful alternative in the mathematical study of computational systems, particularly in connection with algorithms, databases and programs. In this talk we will introduce cyclic proofs and study the extent to which these classes of proofs lend themselves to traditional proof theoretic techniques.

14:00 pm - 16:00 pm
Eugenio Orlandelli: "Labelled calculi for logics of strict and super-strict implication "

Abstract: This talk is about proof systems for logics of strict and super-strict implication. Labelled sequent calculi for C.I. Lewis' logics of strict implication S1-S5 and for their super-strict companions SS1-SS5 are introduced. It is shown that all calculi have good structural properties and are sound and complete. We also outline a compete axiomatisation of the logics SS2-SS5. Finally, it is shown that the labelled calculi for S1 and SS1 have a terminating proof-search strategy.