Well-Formed Formula
See: Logic Sentence.
References
- (Wikipedia, 2009) ⇒ http://en.wikipedia.org/wiki/Well-formed_formula
- In computer science and mathematical logic, a well-formed formula or simply formula[1] (often abbreviated WFF, pronounced "wiff" or "wuff") is a symbol or string of symbols that is generated by the formal grammar of a formal language. To say that a string \ S is a WFF with respect to a given formal grammar \ G is equivalent to saying that \ S belongs to the language generated by \ G. A formal language can be identified with the set of its WFFs.
- A key use of WFFs is in propositional logic and predicate logics such as first-order logic. In those contexts, a formula is a string of symbols φ for which it makes sense to ask "is φ true?", once any free variables in φ have been instantiated.
- In formal logic, proofs can be represented by sequences of WFFs with certain properties, and the final WFF in the sequence is what is proven. This final WFF is called a theorem when it plays a significant role in the theory being developed, or a lemma when it plays an accessory role in the proof of a theorem.
- http://en.wiktionary.org/wiki/well-formed_formula
- A statement that is expressed in a valid, syntactically correct, manner
- http://www.coli.uni-saarland.de/projects/milca/courses/comsem/xhtml/d0e1-gloss.xhtml
- FOL: formulae that are built from a vocabulary, the logical symbols of FOL and first-order variables according to the syntax rules of FOL.
- CYC Glossary http://www.cyc.com/cycdoc/ref/glossary.html