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**well-formed formula**— At its most general a formula may be thought of in logical theory as any string of symbols from the lexicon of the theory. A well formed formula (abbreviated as wff) is one that obeys the formation rules of the system. Since other strings are… … Philosophy dictionary**Well-formed formula**— In mathematical logic, a well formed formula (often abbreviated WFF, pronounced wiff or wuff ) is a symbol or string of symbols (a formula) that is generated by the formal grammar of a formal language. To say that a string S is a WFF with respect … Wikipedia**Monoidal t-norm logic**— Monoidal t norm based logic (or shortly MTL), the logic of left continuous t norms, is one of t norm fuzzy logics. It belongs to the broader class of substructural logics, or logics of residuated lattices;[1] it extends the logic of commutative… … Wikipedia**Metalogic**— is the study of the metatheory of logic. While logic is the study of the manner in which logical systems can be used to decide the correctness of arguments, metalogic studies the properties of the logical systems themselves.[1] According to… … Wikipedia**formation rules**— The formation rules of a logical calculus or formal language lay down which sequences of expressions are to count as well formed . Typically these rules are recursive in character, and contain three kinds of clauses. There will be rules defining… … Philosophy dictionary**Formal proof**— See also: mathematical proof, proof theory, and axiomatic system A formal proof or derivation is a finite sequence of sentences (called well formed formulas in the case of a formal language) each of which is an axiom or follows from the… … Wikipedia**logic, many-valued**— Formal system in which the well formed formulae are interpreted as being able to take on values other than the two classical values of truth or falsity. The number of values possible for well formed formulae in systems of many valued logic ranges … Universalium**Atomic formula**— In mathematical logic, an atomic formula (also known simply as an atom) is a formula with no deeper propositional structure, that is, a formula that contains no logical connectives or equivalently a formula that has no strict subformulas. Atoms… … Wikipedia**Predicate variable**— In first order logic, a predicate variable is a predicate letter which can stand for a relation (between terms) but which has not been specifically assigned any particular relation (or meaning). In first order logic (FOL) they can be more… … Wikipedia**Entailment**— For other uses, see Entail (disambiguation). In logic, entailment is a relation between a set of sentences (e.g.,[1] meaningfully declarative sentences or truthbearers) and a sentence. Let Γ be a set of one or more sentences; let S1 be the… … Wikipedia