The Properties of Similarity for Jonsson’s Theories and Their Models

Abstract

Actually, we study the connections of the Δ-PJ-theories with their centers. The properties of various com-panions of some Δ-PJ-theories and their connection with this theory are considered. Also the similarity of the central types of Δ-PJ-theories in the enriched language is considered. In the class of perfect Δ-PJ-theories the conditions of coincidence of algebraic primeness with some sort of atomic models are found. In the class of Δ-PJ-theories, the concepts of syntactic and semantic similarities are introduced and the results on the relationship of these similarities in this class with their centers are obtained.