Free and non-free subgroups of the fundamental group of the Hawaiian Earrings

Andreas Zastrow

Displaying similar documents to “Free and non-free subgroups of the fundamental group of the Hawaiian Earrings”

Extremal infinite overlap-free binary words.

Allouche, Jean-Paul, Currie, James, Shallit, Jeffrey (1998)

The Electronic Journal of Combinatorics [electronic only]

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There are ternary circular square-free words of length $n$ for $n \geq$ 18.

Currie, James D. (2002)

The Electronic Journal of Combinatorics [electronic only]

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The minimal density of a letter in an infinite ternary square-free word is $0 \cdot 2746 \dots$ .

Tarannikov, Yuriy (2002)

Journal of Integer Sequences [electronic only]

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A generator of morphisms for infinite words

Pascal Ochem (2006)

RAIRO - Theoretical Informatics and Applications

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We present an algorithm which produces, in some cases, infinite words avoiding both large fractional repetitions and a given set of finite words. We use this method to show that all the ternary patterns whose avoidability index was left open in Cassaigne's thesis are 2-avoidable. We also prove that there exist exponentially many ${\frac{7}{4}}^{+}$ -free ternary words and ${\frac{7}{5}}^{+}$ -free 4-ary words. Finally we give small morphisms for binary words containing only the squares , 1 and (01)² and for binary words...

Bordered conjugates of words over large alphabets.

Harju, Tero, Nowotka, Dirk (2008)

The Electronic Journal of Combinatorics [electronic only]

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A note on antichains of words.

Currie, James D. (1995)

The Electronic Journal of Combinatorics [electronic only]

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There exist binary circular $5 / 2^{+}$ power free words of every length.

Aberkane, Ali, Currie, James D. (2004)

The Electronic Journal of Combinatorics [electronic only]

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On ternary square-free circular words.

Shur, Arseny M. (2010)

The Electronic Journal of Combinatorics [electronic only]

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