59 research outputs found

    Binary words containing infinitely many overlaps

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    We characterize the squares occurring in infinite overlap-free binary words and construct various alpha power-free binary words containing infinitely many overlaps.Comment: 9 page

    Generalized Thue-Morse words and palindromic richness

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    We prove that the generalized Thue-Morse word tb,m\mathbf{t}_{b,m} defined for b2b \geq 2 and m1m \geq 1 as tb,m=(sb(n)modm)n=0+\mathbf{t}_{b,m} = (s_b(n) \mod m)_{n=0}^{+\infty}, where sb(n)s_b(n) denotes the sum of digits in the base-bb representation of the integer nn, has its language closed under all elements of a group DmD_m isomorphic to the dihedral group of order 2m2m consisting of morphisms and antimorphisms. Considering simultaneously antimorphisms ΘDm\Theta \in D_m, we show that tb,m\mathbf{t}_{b,m} is saturated by Θ\Theta-palindromes up to the highest possible level. Using the terminology generalizing the notion of palindromic richness for more antimorphisms recently introduced by the author and E. Pelantov\'a, we show that tb,m\mathbf{t}_{b,m} is DmD_m-rich. We also calculate the factor complexity of tb,m\mathbf{t}_{b,m}.Comment: 11 page

    FACTOR AND PALINDROMIC COMPLEXITY OF THUE-MORSE’S AVATARS

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    Two infinite words that are connected with some significant univoque numbers are studied. It is shown that their factor and palindromic complexities almost coincide with the factor and palindromic complexities of the famous Thue-Morse word

    Words with the Maximum Number of Abelian Squares

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    An abelian square is the concatenation of two words that are anagrams of one another. A word of length nn can contain Θ(n2)\Theta(n^2) distinct factors that are abelian squares. We study infinite words such that the number of abelian square factors of length nn grows quadratically with nn.Comment: To appear in the proceedings of WORDS 201

    A relative of the Thue-Morse sequence

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    We study a sequence, c, which encodes the lengths of blocks in the Thue-Morse sequence. In particular, we show that the generating function for c is a simple product
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