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21 votes
6 answers
2k views

Are there uncountably many cube-free infinite binary words?

In Cube-free infinite binary words it was established that there are infinitely many cube-free infinite binary words (see the earlier question for definitions of terms). The construction given in ...
Gerry Myerson's user avatar
12 votes
1 answer
544 views

Is the set of cube-free binary sequences perfect?

This question is inspired by this one. In that thread, it's established that there are uncountably many cube-free infinite binary strings (where $x \in 2^{\omega}$ is cube-free iff $\forall \sigma \...
Amit Kumar Gupta's user avatar
8 votes
1 answer
319 views

Über theorem on unavoidable patterns?

Let $A$ be an alphabet of $k$ symbols, and $p$ a pattern. An example of a pattern is $p=XX$, where $X$ is any finite string of symbols from $A^+$. Avoiding $p$ is avoiding any subword repeated twice ...
Joseph O'Rourke's user avatar
6 votes
2 answers
319 views

Uniqueness of "Limit" of Cyclic Binary Strings

Set-up: By abuse, let $\sigma$ represent both the left shift operator on infinite bi-infinite strings and the cyclic left shift operator on finite strings. (Thus, for example, $\sigma(...01\bar{0}10......
Adam Quinn Jaffe's user avatar
4 votes
1 answer
260 views

Word combinatorics terminology question

I'm looking for the name of what I suspect must be a standard property, and also for a possible statement about that property. First the property: $W=a_0\ldots a_{n-1}$ has this property if for all $1\...
Anthony Quas's user avatar
  • 23.2k
2 votes
3 answers
639 views

The critical exponent function

It is a known fact [1] that, for every $c\in (1,\infty]$, it is possible to find a finite alphabet $\mathcal{A}$ and a word $w\in \mathcal{A}^\omega$ such that $w$ has critical exponent $c$. It looks ...
Alessandro Della Corte's user avatar