1 research outputs found
Characteristic Formulas 50 Years Later (An Algebraic Account)
The Jankov (characteristic) formulas were introduced by V.Jankov fifty tears
ago in 1963. Nowadays the Jankov (or frame) formulas are used in virtually
every branch of propositional logic: intermediate, modal, fuzzy, relevant,
many-valued, etc. All these different logics have one thing in common: in one
form or the other, they admit the deduction theorem. From a standpoint of
algebraic logic it means that their corresponding varieties have a ternary
deductive (TD) term. It is natural to extend the notion of characteristic
formula to such varieties and, thus, apply this notion to an even broader class
of logics, namely, to the logics which algebraic semantic is a variety with a
TD term