Sentence examples for formula is a valid from inspiring English sources

Having defined the basics of the language, now it is necessary to introduce the notion of validity, which allows us to affirm that a given formula is a valid one.

Therefore, although PFL is sound on supervaluational semantics and every semantically valid formula is a theorem of PFL, not all semantically valid sequents are provable in PFL.

Moreover, OA is true at a world a if and only if A is true at every world accessible to a. Thus, if A is a valid formula, then so is OA.

By a well-known result due to Gödel (1933) and McKinsey & Tarski (1948), intuitionistic propositional logic can be interpreted in S4, via a translation t such that φ is intuitionistically provable iff t is a valid S4 formula.

A formula is valid on a supervaluational semantics if and only if it is true on all supervaluations.

The b max is determined as max b ; b = 1, …, u for which the following formula is still valid: b j, a v − ∑ i = 1 b b i, r e q ≥ 0 (7).

This formula is valid in a time-averaged sense for ω > 0.

It is straightforward to check that this formula is valid in a frame if and only if the frame is irreflexive.

The formula is valid for a wide range of parameter values and yields the exact theoretical result under several limiting conditions.

This formula is valid for a long chain in the narrow slit in the subcritical regime or when the adsorption layer h>D in the adsorptive regime.

More exactly, while it is true that, if a formula is valid, one can eventually find a proof of it in the logic, there is in general no proof theoretic way to determine that a formula is invalid.