• logic, the LöwenheimSkolem theorem is a theorem on the existence and cardinality of models, named after Leopold Löwenheim and Thoralf Skolem. The precise...
    22 KB (2,795 words) - 12:03, 4 October 2024
  • Thumbnail for Skolem's paradox
    from part of the LöwenheimSkolem theorem; Thoralf Skolem was the first to discuss the seemingly contradictory aspects of the theorem, and to discover...
    28 KB (3,331 words) - 13:07, 20 June 2025
  • Thumbnail for Leopold Löwenheim
    resumed teaching mathematics. Löwenheim (1915) gave the first proof of what is now known as the LöwenheimSkolem theorem, often considered the starting...
    7 KB (467 words) - 10:35, 21 August 2024
  • compactness theorem is one of the two key properties, along with the downward LöwenheimSkolem theorem, that is used in Lindström's theorem to characterize...
    14 KB (1,946 words) - 02:43, 16 June 2025
  • Thumbnail for Thoralf Skolem
    greatly simplified the proof of a theorem Leopold Löwenheim first proved in 1915, resulting in the LöwenheimSkolem theorem, which states that if a countable...
    12 KB (1,513 words) - 04:02, 31 January 2025
  • amenable to analysis in proof theory, such as the LöwenheimSkolem theorem and the compactness theorem. First-order logic is the standard for the formalization...
    93 KB (12,955 words) - 20:50, 1 July 2025
  • the downward LöwenheimSkolem theorem, published by Leopold Löwenheim in 1915. The compactness theorem was implicit in work by Thoralf Skolem, but it was...
    63 KB (9,064 words) - 09:00, 2 July 2025
  • model theory is the LöwenheimSkolem theorem, which can be proven via Skolemizing the theory and closing under the resulting Skolem functions. In general...
    11 KB (1,909 words) - 06:27, 25 July 2024
  • automation. In 1920, Thoralf Skolem simplified a previous result by Leopold Löwenheim, leading to the LöwenheimSkolem theorem and, in 1930, to the notion...
    29 KB (2,933 words) - 22:11, 19 June 2025
  • independence results in set theory. Leopold Löwenheim and Thoralf Skolem obtained the LöwenheimSkolem theorem, which says that first-order logic cannot...
    69 KB (8,370 words) - 19:12, 10 June 2025
  • subsets of the domain. It follows from the compactness theorem and the upward LöwenheimSkolem theorem that it is not possible to characterize finiteness...
    32 KB (4,502 words) - 01:10, 13 April 2025
  • elementarily equivalent models, which can be obtained via the LöwenheimSkolem theorem. Thus, for example, there are non-standard models of Peano arithmetic...
    8 KB (956 words) - 00:42, 21 September 2023
  • mathematical logic the Löwenheim number of an abstract logic is the smallest cardinal number for which a weak downward LöwenheimSkolem theorem holds. They are...
    5 KB (654 words) - 09:14, 28 August 2024
  • Gödel's incompleteness theorems are two theorems of mathematical logic that are concerned with the limits of provability in formal axiomatic theories...
    92 KB (12,173 words) - 02:29, 24 June 2025
  • models are isomorphic. It follows from the definition above and the LöwenheimSkolem theorem that any first-order theory with a model of infinite cardinality...
    10 KB (1,157 words) - 04:00, 24 March 2025
  • Thumbnail for Gödel's completeness theorem
    LöwenheimSkolem theorem, says: Every syntactically consistent, countable first-order theory has a finite or countable model. Given Henkin's theorem,...
    17 KB (2,330 words) - 17:38, 29 January 2025
  • {\displaystyle \Rightarrow } LöwenheimSkolem theorem" — that is, D C {\displaystyle {\mathsf {DC}}} implies the LöwenheimSkolem theorem. See table Moore, Gregory...
    9 KB (950 words) - 00:45, 27 July 2024
  • (countable) compactness property and the (downward) LöwenheimSkolem property. Lindström's theorem is perhaps the best known result of what later became...
    4 KB (386 words) - 21:19, 3 March 2025
  • Thumbnail for Theorem
    undefinability theorem Church-Turing theorem of undecidability Löb's theorem LöwenheimSkolem theorem Lindström's theorem Craig's theorem Cut-elimination theorem The...
    34 KB (4,409 words) - 00:49, 4 April 2025
  • Thumbnail for Original proof of Gödel's completeness theorem
    \varphi } . The following lemma, which Gödel adapted from Skolem's proof of the LöwenheimSkolem theorem, lets us sharply reduce the complexity of the generic...
    26 KB (4,798 words) - 17:08, 18 October 2024
  • infinite model; this affects the statements of results such as the LöwenheimSkolem theorem, which are usually stated under the assumption that only normal...
    32 KB (4,478 words) - 03:26, 11 May 2025
  • logic) Lindström's theorem (mathematical logic) Löb's theorem (mathematical logic) Łoś' theorem (model theory) LöwenheimSkolem theorem (mathematical logic)...
    78 KB (6,292 words) - 23:25, 29 June 2025
  • compactness theorem implies that the existence of nonstandard elements cannot be excluded in first-order logic. The upward LöwenheimSkolem theorem shows that...
    49 KB (6,478 words) - 03:13, 3 April 2025
  • Thumbnail for Real number
    possible to characterize the reals with first-order logic alone: the LöwenheimSkolem theorem implies that there exists a countable dense subset of the real...
    61 KB (8,195 words) - 20:54, 2 July 2025
  • Ultraproduct (redirect from Los's theorem)
    propertiesPages displaying wikidata descriptions as a fallback LöwenheimSkolem theorem – Existence and cardinality of models of logical theories Transfer...
    18 KB (3,108 words) - 20:35, 16 August 2024
  • This set is called the minimal model of ZFC. Using the downward LöwenheimSkolem theorem, one can show that the minimal model (if it exists) is a countable...
    32 KB (6,103 words) - 15:18, 3 May 2025
  • necessitates the truth of another. downward LöwenheimSkolem theorem Part of the LöwenheimSkolem theorem. doxastic modal logic A branch of modal logic...
    271 KB (30,237 words) - 18:29, 25 April 2025
  • Cantor's contradictions. 1915 - Leopold Löwenheim publishes a proof of the (downward) Löwenheim-Skolem theorem, implicitly using the axiom of choice. 1918...
    8 KB (948 words) - 20:52, 17 February 2025
  • is a minimal standard model (see Constructible universe). The LöwenheimSkolem theorem can be used to show that this minimal model is countable. The fact...
    28 KB (4,381 words) - 01:01, 29 March 2025
  • 1920: Thoralf Skolem corrected Leopold Löwenheim's proof of what is now called the downward LöwenheimSkolem theorem, leading to Skolem's paradox discussed...
    52 KB (6,910 words) - 08:29, 16 June 2025