Valuation (logic)
In logic and model theory, a valuation can be:
- In propositional logic, an assignment of truth values to propositional variables, with a corresponding assignment of truth values to all propositional formulas with those variables.[1][2]
- In first-order logic and higher-order logics, a structure, (the interpretation) and the corresponding assignment of a truth value to each sentence in the language for that structure (the valuation proper). The interpretation must be a homomorphism, while valuation is simply a function.[3]
Mathematical logic
[edit]In mathematical logic (especially model theory), a valuation is an assignment of truth values to formal sentences that follows a truth schema. Valuations are also called truth assignments.[4] In propositional logic, there are no quantifiers, and formulas are built from propositional variables using logical connectives[5][6]. In this context, a valuation begins with an assignment of a truth value to each propositional variable. This assignment can be uniquely extended to an assignment of truth values to all propositional formulas.[7]
In first-order logic, a language consists of a collection of constant symbols, a collection of function symbols, and a collection of relation symbols. Formulas are built out of atomic formulas using logical connectives and quantifiers. A structure consists of a set (domain of discourse) that determines the range of the quantifiers, along with interpretations of the constant, function, and relation symbols in the language. Corresponding to each structure is a unique truth assignment for all sentences (formulas with no free variables) in the language.
Notation
[edit]If is a valuation, that is, a mapping from the atoms to the set , then the double-bracket notation is commonly used to denote a valuation; that is, for a proposition .[8]
![{\displaystyle v(\phi )=[\![\phi ]\!]_{v}}](https://cdn.statically.io/img/wikimedia.org/api/rest_v1/media/math/render/svg/2916578afb82db0a70fdaf16c7bca249addee421)
See also
[edit]References
[edit]- ^ Smullyan, Raymond M. (2016-11-11). A Beginner's Further Guide To Mathematical Logic. World Scientific Publishing Company. p. 9. ISBN 978-981-4733-01-4.
- ^ Sabry, Fouad (2023-06-24). Propositional Logic: Fundamentals and Applications. One Billion Knowledgeable.
- ^ Manzano, Maria (1996-03-29). Extensions of First-Order Logic. Cambridge University Press. p. 227. ISBN 978-0-521-35435-6.
- ^ Intelligence, European Coordinating Committee for Artificial (2008). ECAI 2008: 18th European Conference on Artificial Intelligence, July 21-25, 2008, Patras, Greece : Including Prestigious Applications of Intelligent Systems (PAIS 2008) : Proceedings. IOS Press. p. 351. ISBN 978-1-58603-891-5.
- ^ Hamilton, A. G. (1988-09-29). Logic for Mathematicians. Cambridge University Press. p. 91. ISBN 978-0-521-36865-0.
- ^ "Dịch Vụ Viết Thuê Assignment". Retrieved 2024-08-06.
- ^ Ono, Hiroakira (2019-08-02). Proof Theory and Algebra in Logic. Springer. p. 6. ISBN 978-981-13-7997-0.
- ^ Dirk van Dalen, (2004) Logic and Structure, Springer Universitext, (see section 1.2) ISBN 978-3-540-20879-2
Further reading
[edit]- Rasiowa, Helena; Sikorski, Roman (1970), The Mathematics of Metamathematics (3rd ed.), Warsaw: PWN, chapter 6 Algebra of formalized languages.
- J. Michael Dunn; Gary M. Hardegree (2001). Algebraic methods in philosophical logic. Oxford University Press. p. 155. ISBN 978-0-19-853192-0.