Difference between revisions of "Entscheidungsproblem"

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== See also ==
 
== See also ==
  
 +
* [[Alan Turing]]
 
* [[Algorithm]]
 
* [[Algorithm]]
* [[Alonzo Church|Church, Alonzo]]
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* [[Alonzo Church]]
 
* [[Lambda calculus]]
 
* [[Lambda calculus]]
* [[Alan Turing|Turing, Alan]]
 
 
* [[Turing machine]]
 
* [[Turing machine]]
 
* [[Undecidable problem]]
 
* [[Undecidable problem]]

Latest revision as of 12:44, 24 April 2016

In mathematics and computer science, the Entscheidungsproblem (pronounced [ɛntˈʃaɪ̯dʊŋspʁoˌbleːm], German for 'decision problem') is a challenge posed by David Hilbert in 1928.

Description

The Entscheidungsproblem asks for an algorithm that takes as input a statement of a first-order logic (possibly with a finite number of axioms beyond the usual axioms of first-order logic) and answers "Yes" or "No" according to whether the statement is universally valid, i.e., valid in every structure satisfying the axioms.

By the completeness theorem of first-order logic, a statement is universally valid if and only if it can be deduced from the axioms, so the Entscheidungsproblem can also be viewed as asking for an algorithm to decide whether a given statement is provable from the axioms using the rules of logic.

In 1936, Alonzo Church and Alan Turing published independent papers showing that a general solution to the Entscheidungsproblem is impossible, assuming that the intuitive notion of "effectively calculable" is captured by the functions computable by a Turing machine (or equivalently, by those expressible in the lambda calculus).

This assumption is now known as the Church–Turing thesis.

See also

External links