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In data compression and the theory of formal languages, the smallest grammar problem is the problem of finding the smallest context-free grammar that generates a given string of characters (but no other string). The size of a grammar is defined by some authors as the number of symbols on the right side of the production rules. [1] Others also add the number of rules to that. [2] The (decision version of the) problem is NP-complete. [1] The smallest context-free grammar that generates a given string is always a straight-line grammar without useless rules.[ citation needed]

See also

References

  1. ^ a b Charikar, Moses; Lehman, Eric; Liu, Ding; Panigrahy, Rina; Prabhakaran, Manoj; Sahai, Amit; Shelat, Abhi (2005). "The Smallest Grammar Problem". IEEE Transactions on Information Theory. 51 (7): 2554–2576. CiteSeerX  10.1.1.185.2130. doi: 10.1109/TIT.2005.850116. S2CID  6900082. Zbl  1296.68086.
  2. ^ Florian Benz and Timo Kötzing, “An effective heuristic for the smallest grammar problem,” Proceedings of the fifteenth annual conference on Genetic and evolutionary computation conference - GECCO ’13, 2013. ISBN  978-1-4503-1963-8 doi: 10.1145/2463372.2463441