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Universal Lyndon Words

ŠTěpán HolubJakub OpršalArturo CarpiMarinella SciortinoGabriele Fici

subject

Discrete mathematicsExistential quantificationLyndon word Universal cycle Universal Lyndon wordComputer Science::Computation and Language (Computational Linguistics and Natural Language and Speech Processing)Lyndon word Universal cycle Universal Lyndon word Lex-codeLexicographical orderLyndon wordUniversal Lyndon wordLyndon wordsPrefixCombinatoricsMathematics::Group TheoryCombinatorics on wordsComputer Science::Discrete MathematicsUniversal cycleBijectionAlphabetMathematics::Representation TheoryComputer Science::Formal Languages and Automata TheoryMathematics

description

A word w over an alphabet Σ is a Lyndon word if there exists an order defined on Σ for which w is lexicographically smaller than all of its conjugates (other than itself). We introduce and study universal Lyndon words, which are words over an n-letter alphabet that have length n! and such that all the conjugates are Lyndon words. We show that universal Lyndon words exist for every n and exhibit combinatorial and structural properties of these words. We then define particular prefix codes, which we call Hamiltonian lex-codes, and show that every Hamiltonian lex-code is in bijection with the set of the shortest unrepeated prefixes of the conjugates of a universal Lyndon word. This allows us to give an algorithm for constructing all the universal Lyndon words.

10.1007/978-3-662-44522-8_12http://hdl.handle.net/10447/96795