Separating Words with Small Grammars

نویسندگان

  • James D. Currie
  • Holger Petersen
  • John Michael Robson
  • Jeffrey Shallit
چکیده

We study the following problem: given two words w and x, with jwj; jxj n, what is the size of the smallest context-free grammar G which generates exactly one of fw; xg? If jwj 6 = jxj, then we prove there exists a G separating w from x of size O(log log n), and this bound is best possible. If jwj = jxj, then we get an upper bound on the size of G of O(log n), and a lower bound of (logn loglog n).

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عنوان ژورنال:
  • Journal of Automata, Languages and Combinatorics

دوره 4  شماره 

صفحات  -

تاریخ انتشار 1999