Abstract

A “semantic frame” is bounded join-semilattice of elementary situations, with its maximal ideals to represent possible worlds and mapped into the complete sets of propositions determined by a given abstract logic . A frame is Humean if the elementary situations are separated by its possible worlds, and it is atomistic if the semilattice is so. One frame is the extension of another if the latter is an {0,1}-subsemilattice of the former satisfying certain conditions discussed