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 {{harvs|first=Jerzy|last=Łoś|authorlink=Jerzy Łoś|year=1954|txt}} and {{harvs|first= Robert L.|last= Vaught |authorlink=Robert Lawson Vaught |year=1954|txt}}, after whom it is named.
See also
- {{annotated link|Robinson's joint consistency theorem}}
References
{{reflist}}
- {{citation
| last = Enderton | first = Herbert B. | authorlink = Herbert Enderton
| mr = 0337470
| page = 147
| publisher = Academic Press, New York-London
| title = A mathematical introduction to logic
| url = https://books.google.com/books?id=LHjNCgAAQBAJ&pg=PA147
| year = 1972| isbn = 978-0-08-057038-9 }}.
- {{citation
| last = Łoś | first = Jerzy | authorlink = Jerzy Łoś
| journal = Colloquium Mathematicum
| mr = 0061561
| pages = 58–62
| title = On the categoricity in power of elementary deductive systems and some related problems
| volume = 3
| year = 1954| doi = 10.4064/cm-3-1-58-62 }}.
- {{citation
| last = Vaught | first = Robert L. | authorlink = Robert Lawson Vaught
| journal = Indagationes Mathematicae
| mr = 0063993
| pages = 467–472
| title = Applications to the Löwenheim-Skolem-Tarski theorem to problems of completeness and decidability
| volume = 16
| year = 1954| doi = 10.1016/S1385-7258(54)50058-2 }}.
{{Mathematical logic}}
{{DEFAULTSORT:Los-Vaught test}}