Characteristic formulas over intermediate logics
نویسنده
چکیده
We expand the notion of characteristic formula to infinite finitely presentable subdirectly irreducible algebras. We prove that there is a continuum of varieties of Heyting algebras containing infinite finitely presentable subdirectly irreducible algebras. Moreover, we prove that there is a continuum of intermediate logics that can be axiomatized by characteristic formulas of infinite algebras while they are not axiomatizable by standard Jankov formulas. We give the examples of intermediate logics that are not axiomatizable by characteristic formulas of infinite algebras. Also, using the Gödel-McKinsey-Tarski translation we extend these results to the varieties of interior algebras and normal extensions of S4.
منابع مشابه
The density of truth in monadic fragments of some intermediate logics
This paper is an attempt to count the proportion of tautologies of some intermediate logics among all formulas. Our interest concentrates especially on Dummett’s and Medvedev’s logics and their {→,∨,¬} fragments over language with one propositional variable.
متن کاملJankov Formula and Ternary Deductive Term
Jankov (characteristic) formulas were introduced 50 years ago in [7] and proved to be a very useful tool for studying a broad range of logics, e.g. intermediate, modal, fuzzy, relevant, many-valued, etc. All these different logics have one thing in common: in one or the other form they admit the deduction theorem. From the standpoint of algebraic logic it means that their corresponding varietie...
متن کاملFrame Based Formulas for Intermediate Logics
In this paper we define the notion of frame based formulas. We show that the well-known examples of formulas arising from a finite frame, such as the Jankov-de Jongh formulas, subframe formulas and cofinal subframe formulas, are all particular cases of the frame based formulas. We give a criterion for an intermediate logic to be axiomatizable by frame based formulas and use this criterion to ob...
متن کاملCanonical Formulas for Wk4
We generalize the theory of canonical formulas for K4 (the logic of transitive frames) to wK4 (the logic of weakly transitive frames). Our main result establishes that each logic over wK4 is axiomatizable by canonical formulas, thus generalizing Zakharyaschev’s theorem for logics over K4. The key new ingredients include the concepts of transitive and strongly cofinal subframes of weakly transit...
متن کاملTools for the Investigation of Substructural, Intermediate and Paraconsistent Logics
Non-classical logics have gained importance in many fields of computer science, engineering and philosophy. They are often employed in applications of artificial intelligence, knowledge representation and formal verification; e.g., when it comes to reasoning in presence of vague information or inconsistencies. There are already many non-classical logics and, due to the increasing demand for suc...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- CoRR
دوره abs/1208.2631 شماره
صفحات -
تاریخ انتشار 2012