Łoś–Vaught test
In model theory, a branch of mathematical logic, the Łoś–Vaught test is a criterion for a theory to be complete, unable to be augmented without becoming inconsistent. For theories in classical logic, this means that for every sentence, the theory contains either the sentence or its negation but not both.
Statement
A theory with signature σ is -categorical for an infinite cardinal if has exactly one model (up to isomorphism) of cardinality
The Łoś–Vaught test states that if a satisfiable theory is -categorical for some and has no finite model, then it is complete.
This theorem was proved independently by Jerzy Łoś (1954) and Robert L. Vaught (1954), after whom it is named.
See also
- Robinson's joint consistency theorem – Theorem of mathematical logic
References
- Enderton, Herbert B. (1972), A mathematical introduction to logic, Academic Press, New York-London, p. 147, MR 0337470.
- Łoś, Jerzy (1954), "On the categoricity in power of elementary deductive systems and some related problems", Colloquium Mathematicum, 3: 58–62, MR 0061561.
- Vaught, Robert L. (1954), "Applications to the Löwenheim-Skolem-Tarski theorem to problems of completeness and decidability", Indagationes Mathematicae, 16: 467–472, MR 0063993.
- v
- t
- e
Mathematical logic
- Axiom
- list
- Cardinality
- First-order logic
- Formal proof
- Formal semantics
- Foundations of mathematics
- Information theory
- Lemma
- Logical consequence
- Model
- Theorem
- Theory
- Type theory
and paradoxes
Traditional | |
---|---|
Propositional | |
Predicate |
|
| |
Types of sets |
|
---|---|
Maps and cardinality |
|
Set theories |
language and syntax
| |
Example axiomatic systems (list) |
---|
- Interpretation
- function
- of models
- Model
- equivalence
- finite
- saturated
- spectrum
- submodel
- Non-standard model
- Diagram
- Categorical theory
- Model complete theory
- Satisfiability
- Semantics of logic
- Strength
- Theories of truth
- T-schema
- Transfer principle
- Truth predicate
- Truth value
- Type
- Ultraproduct
- Validity
![icon](http://upload.wikimedia.org/wikipedia/commons/thumb/3/3e/Nuvola_apps_edu_mathematics_blue-p.svg/16px-Nuvola_apps_edu_mathematics_blue-p.svg.png)