On exact conditionals.
On logical wholeness of an (axiomatic) formal theory
On reproductive solutions of Boolean equations.
On The Greatest Congruence Of Relations
On the greatest congruence of relations.
On the Leibniz congruences
The aim of this paper is to discuss the motivation for a new general algebraic semantics for deductive systems, to introduce it, and to present an outline of its main features. Some tools from the theory of abstract logics are also introduced, and two classifications of deductive systems are analysed: one is based on the behaviour of the Leibniz congruence (the maximum congruence of a logical matrix) and the other on the behaviour of the Frege operator (which associates to every theory the interderivability...