Title: Stable Canonical Formulas and Rules and Their Applications

Speaker: Nick Bezhanishvili (UvA)

Time: May 26th (Tuesday), 15:10 - 18:00

Location: Room 314, Teaching Building No.2 (北京大学第二教学楼314)

Abstract:

In this talk, I will first review the Esakia and Jónsson-Tarski dualities for Heyting and modal algebras. I will then show how these dualities can be used to develop a theory of stable canonical formulas and rules, and how every superintuitionistic and modal logic can be axiomatized by such formulas and rules. 

In the final part of the talk, I will present several applications of the method of stable canonical formulas and rules. In particular, I will explain how these methods yield an alternative and rather transparent geometric proof of the Blok-Esakia Theorem - one of the central results in superintuitionistic modal logics - stating that the lattice of superintuitionistic logics is isomorphic to the lattice of extensions of the modal logic Grz.