An infinite square-free co-CFL
Information Processing Letters
Non-repetitive colorings of infinite sets
Discrete Mathematics
Finding All Approximate Gapped Palindromes
ISAAC '09 Proceedings of the 20th International Symposium on Algorithms and Computation
Counting and verifying maximal palindromes
SPIRE'10 Proceedings of the 17th international conference on String processing and information retrieval
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We answer a question of Bresar et al. about the structure of non-repetitive words: For any sequence A of positive integers with large enough gaps, there is a ternary non-repetitive word having a length 3 palindrome starting at each position a@?A. In fact, we can find ternary non-repetitive words such that for each a@?A, the length 3 subword starting at position a is a palindrome or not, as one chooses. This arbitrariness in the positioning of subwords contrasts markedly with the situation for binary overlap-free words.