On Independent Axiomatizability of Quasi-Normal Modal Logics

Studia Logica - We give a negative solution to the problem, posed by A. Chagrov and M. Zakharyaschev, of whether every quasi-normal propositional modal logic can be axiomatized by an independent...     

On the structure of lattices of subquasivarieties of congruence-noetherian quasivarieties

We study the structure of algebraic -closed subsets of an algebraic lattice L, where is some Browerian binary relation on L, in the special case when the lattice of such subsets is an atomistic lattice. This gives an approach to investigate the atomistic lattices of congruence-Noetherian quasivarieties.V. A. Gorbunov has died in January 1999Special issue of Studia Logica: Algebraic Theory of Quasivarieties Presented by M. E. Adams, W. Dziobiak, and A. V. Kravchenko