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Trakhtenbrot's Theorem

Logic and Foundations

Trakhtenbrot's Theorem states that the set of first-order sentences valid on every finite structure is not decidable, meaning no algorithm can determine in general whether a given first-order sentence holds in all finite models. Named for Boris Trakhtenbrot, it shows that finite model theory does not inherit the completeness and decidability properties available for first-order logic over arbitrary structures, since validity on finite models and validity in general diverge in this fundamental way.

Facts
Statement
The problem of validity in first-order logic on the class of all finite models is undecidable. 1
Proof Year
1950 1
Classification
Statement Form
Impossibility Theorem 1
Connections

Has Statement Form

In Branch

Source Trakhtenbrot's theorem (Wikipedia)
Source Trakhtenbrot's theorem (Wikipedia)

Principal Result Of

Source Boris Trakhtenbrot (Wikipedia)

Proved By

Source Trakhtenbrot's theorem (Wikipedia)
In the Other Atlases

Credited To

Also in Computing Atlas: credited with this subject.

Sources
1. Trakhtenbrot's theorem (Wikipedia)
  • Mathematical formulation section
    The problem of validity in first-order logic on the class of all finite models is undecidable.
  • Opening section, publication sentence
    The theorem was first published in 1950
  • Proved By: Boris Trakhtenbrot, Lead sentence
    In logic, finite model theory, and computability theory, Trakhtenbrot's theorem (due to Boris Trakhtenbrot) states that the problem of validity in first-order logic on the class of all finite models is undecidable.
  • In Branch: Model Theory, Lead paragraph
    In logic, finite model theory, and computability theory, Trakhtenbrot's theorem (due to Boris Trakhtenbrot) states that the problem of validity in first-order logic on the class of all finite models is undecidable.
  • In Branch: Computability Theory, Lead paragraph
    In logic, finite model theory, and computability theory, Trakhtenbrot's theorem (due to Boris Trakhtenbrot) states that the problem of validity in first-order logic on the class of all finite models is undecidable.
  • In Group: Mathematical Logic and Model Theory, Lead section
    In logic, finite model theory, and computability theory, Trakhtenbrot's theorem
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Boris Trakhtenbrot (Wikipedia)
Principal Result Of: Boris Trakhtenbrot, Biography, Trakhtenbrot theorem (principal result)
Quote, Principal Result Of: Boris Trakhtenbrot, Biography, Trakhtenbrot theorem (principal result)
He also discovered and proved the theorem in logic, model theory, and computability theory now known as Trakhtenbrot's theorem.
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