Richomme asked the following question:
what is the infimum of the real numbers > 2 such that
there exists an infinite word that avoids -powers but
contains arbitrarily large squares beginning at every position?
We resolve this question in the case of a binary alphabet by showing
that the answer is = 7/3.
We show that Dejean's conjecture
holds for ≥ 27. This brings the final resolution of the conjecture by the approach of Moulin Ollagnier within range of the computationally feasible.
We show that any positive integer is the least period of a factor of the Thue-Morse word. We also characterize the set of least periods of factors of a sturmian word. In particular, the corresponding set for the Fibonacci word is the set of Fibonacci numbers. As a by-product of our results, we give several new proofs and tightenings of well-known properties of sturmian words.
We show that any positive integer is the least period of a factor of the Thue-Morse word.
We also characterize the set of least periods of factors of a Sturmian word. In particular,
the corresponding set for the Fibonacci word is the set of Fibonacci numbers.
As a by-product of our results, we give several new proofs and tightenings
of well-known properties of Sturmian words.
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