17 October 2000, talk by ILLC-guest Valentin Goranko

17 October 2000, talk by ILLC-guest Valentin Goranko
Speaker: Valentin Goranko
Title: Generalizing Sahlqvist formulae(From Sahlqvist to van Benthem: the long and winding road)
Date and Time: Tuesday October 17 2000, 15.15 - 17.00
Location: P.014, Euclides Building, Plantage Muidergracht 24, Amsterdam

Abstract:
We propose a generalization of Sahlqvist formulae to polyadic modal languages by representing these languages in a combinatorial style and thus, in particular, developing what we believe to be the right syntactic approach to Sahlqvist formulae at all. We prove first-order definability and canonicity for the extended class of polyadic Sahlqvist formulae.
In this talk I will outline our approach, give some examples, and mention how in some extended languages Sahlqvist theorem can be obtained as a rather easy syntactic exercise. Finally, I will discuss the question of what Sahlqvist formulae actually are.
This talk is based on joint work with D. Vakarelov.

For more information, contact Yde Venema (yde@science.uva.nl).