Abstract

Fibring is de ned as a mechanism for combining logics with a rstorder base, at both the semantic and deductive levels. A completeness theorem is established for a wide class of such logics, using a variation of the Henkin method that takes advantage of the presence of equality and inequality in the logic. As a corollary, completeness is shown to be preserved when bring logics in that class. A modal rst-order logic is obtained as a bring where neither the Barcan formula nor its converse hold.

Citations