Avoidability of Palindrome Patterns

  • Pascal Ochem
  • Matthieu Rosenfeld

Abstract

We characterize the formulas that are avoided by every α-free word for some α>1. We show that the avoidable formulas whose fragments are of the form XY or XYX are 4-avoidable. The largest avoidability index of an avoidable palindrome pattern is known to be at least 4 and at most 16. We make progress toward the conjecture that every avoidable palindrome pattern is 4-avoidable.

Published
2021-01-15
Article Number
P1.4