Modal logic is a kind of logic used to represent statements about necessity and possibility. In philosophy and related fields it is used as a tool for...

Epistemic modal logic is a subfield of modal logic that is concerned with reasoning about knowledge. While epistemology has a long philosophical tradition...

In logic and philosophy, S5 is one of five systems of modal logic proposed by Clarence Irving Lewis and Cooper Harold Langford in their 1932 book Symbolic...

In logic, philosophy, and theoretical computer science, dynamic logic is an extension of modal logic capable of encoding properties of computer programs...

In logic, a normal modal logic is a set L of modal formulas such that L contains: All propositional tautologies; All instances of the Kripke schema: ◻...

instantiation. Modal logics are formal systems that extend propositional logic and first-order logic with additional logical operators. Alethic modal logic introduces...

something"). It is sometimes also used to refer to tense logic, a modal logic-based system of temporal logic introduced by Arthur Prior in the late 1950s, with...

of logic that studies the application of logical methods to philosophical problems, often in the form of extended logical systems like modal logic. But...

and discourse effects of modal expressions using formal tools derived from modal logic. Within philosophy, linguistic modality is often seen as a window...

can be used to formalize imperative logic, or directive modality in natural languages. Typically, a deontic logic uses OA to mean it is obligatory that...

non-classical logic systems created in the late 1950s and early 1960s by Saul Kripke and André Joyal. It was first conceived for modal logics, and later...

logical systems like modal logic. Some theorists conceive philosophical logic in a wider sense as the study of the scope and nature of logic in general. In...

approaches to the semantics of programming languages. He has also worked on modal logic, topology, and category theory. He received his B.A. in Mathematics from...

satisfiability of finite sets of formulas of various logics. It is the most popular proof procedure for modal logics. A method of truth trees contains a fixed set...

In modal logic, a regular modal logic is a modal logic containing (as axiom or theorem) the duality of the modal operators: ◊ A ↔ ¬ ◻ ¬ A {\displaystyle...

A modal connective (or modal operator) is a logical connective for modal logic. It is an operator which forms propositions from propositions. In general...

and original contributions to logic, especially modal logic. His principal contribution is a semantics for modal logic involving possible worlds, now...

In logic, a modal companion of a superintuitionistic (intermediate) logic L is a normal modal logic that interprets L by a certain canonical translation...

reference work on natural deduction, and included applications for modal and second-order logic. In natural deduction, a proposition is deduced from a collection...

American academic philosopher. He is considered the progenitor of modern modal logic and the founder of conceptual pragmatism. First a noted logician, he...

topology and the modal logic S4 what Boolean algebras are to set theory and ordinary propositional logic. Interior algebras form a variety of modal algebras....

recursion theory and proof theory, but has also led to Löb's theorem in modal logic. The method of forcing is employed in set theory, model theory, and recursion...

In modal logic, Sahlqvist formulas are a certain kind of modal formula with remarkable properties. The Sahlqvist correspondence theorem states that every...

In logic, contingency is the feature of a statement making it neither necessary nor impossible. Contingency is a fundamental concept of modal logic. Modal...

such fine logical structures like modal, temporal, dynamic, epistemic ones). In order to achieve its special goal, logic was forced to develop its own formal...

Provability logic is a modal logic, in which the box (or "necessity") operator is interpreted as 'it is provable that'. The point is to capture the notion...

example, infinitary logics permit formulas of infinite size, and modal logics add symbols for possibility and necessity. First-order logic can be studied in...

In modal logic, modal collapse is the condition in which every true statement is necessarily true, and vice versa; that is to say, there are no contingent...

ethics, and epistemology. Modal logic is an extension of classical logic. In its original form, sometimes called "alethic modal logic", it introduces two new...

logic is a modal logic that has more than one primitive modal operator. They find substantial applications in theoretical computer science. A modal logic...