Encyclopedia > Decidable language

  Article Content

Decidable language

A decidable or recursive language is a formal language for which there exists an algorithm to solve the following decision problem: Given string w, does w belong to the language? The algorithm is not allowed to run into an infinite loop and has to produce a YES/NO answer for any input string after a finite amount of time. To formalize the rather vague term "algorithm", one usually employs Turing machines, but several other equivalent approaches are possible.

All regular, context-free and context-sensitive languages are recursive, but there exist recursively enumerable languages which are not recursive; one example is given by the halting problem.



All Wikipedia text is available under the terms of the GNU Free Documentation License

 
  Search Encyclopedia

Search over one million articles, find something about almost anything!
 
 
  
  Featured Article
Firth

... outlet to the sea. See Pentland Firth. The Firths on the West Coast of Scotland from North to South Firth of Lorn[?] (northernmost, connects with the Moray ...