An Algebraic Approach to Canonical Formulas: Modal Case

作者:Bezhanishvili Guram*; Bezhanishvili Nick
来源:Studia Logica, 2011, 99(1-3): 93-125.
DOI:10.1007/s11225-011-9348-9

摘要

We introduce relativized modal algebra homomorphisms and show that the category of modal algebras and relativized modal algebra homomorphisms is dually equivalent to the category of modal spaces and partial continuous p-morphisms, thus extending the standard duality between the category of modal algebras and modal algebra homomorphisms and the category of modal spaces and continuous p-morphisms. In the transitive case, this yields an algebraic characterization of Zakharyaschev's subreductions, cofinal subreductions, dense subreductions, and the closed domain condition. As a consequence, we give an algebraic description of canonical, subframe, and cofinal subframe formulas, and provide a new algebraic proof of Zakharyaschev's theorem that each logic over K4 is axiomatizable by canonical formulas.

  • 出版日期2011-10