Published online by Cambridge University Press: 12 March 2014
The language of propositional modal logic is extended by the introduction of sequents. Validity of a modal sequent on a frame is defined, and modal sequent-axiomatic classes of frames are introduced. Through the use of modal algebras and general frames, a study of the properties of such classes is begun.
The results of this article are based on an M.Sc. thesis written at Simon Fraser University under the supervision of Dr. S. K. Thomason. The author gratefully acknowledges his supervisor's contribution.