English

Repetitions in infinite palindrome-rich words

Combinatorics 2019-11-15 v1 Formal Languages and Automata Theory

Abstract

Rich words are characterized by containing the maximum possible number of distinct palindromes. Several characteristic properties of rich words have been studied; yet the analysis of repetitions in rich words still involves some interesting open problems. We address lower bounds on the repetition threshold of infinite rich words over 2 and 3-letter alphabets, and construct a candidate infinite rich word over the alphabet Σ2={0,1}\Sigma_2=\{0,1\} with a small critical exponent of 2+2/22+\sqrt{2}/2. This represents the first progress on an open problem of Vesti from 2017.

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Cite

@article{arxiv.1904.10028,
  title  = {Repetitions in infinite palindrome-rich words},
  author = {Aseem Raj Baranwal and Jeffrey Shallit},
  journal= {arXiv preprint arXiv:1904.10028},
  year   = {2019}
}

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12 pages