Now showing items 1-3 of 3
On avoidability of formulas with reversal
(EDP Sciences, 2018-02-13)
While a characterization of unavoidable formulas (without reversal) is well-known, little is known about the avoidability of formulas with reversal in general. In this article, we characterize the unavoidable formulas ...
Avoiding Patterns in the Abelian Sense
(Canadian Mathematical Society, 2001-08)
We classify all 3 letter patterns that are avoidable in the abelian sense. A short list of four letter patterns for which abelian avoidance is undecided is given. Using a generalization of Zimin words we deduce some ...
Words without Near-Repetitions
(Canadian Mathematical Society, 1992-06-01)
We find an infinite word w on four symbols with the following property: Two occurrences of any block in w must be separated by more than the length of the block. That is, in any subword of w of the form xyx, the length of ...