MUTUALLY AVOIDING TERNARY WORDS OF SMALL EXPONENT
Maxime Crochemore, P. Goralčík · International Journal of Algebra and Computation · 1991
We construct, for every ε > 0, an infinite set Sε of words over a three letter alphabet such that every factor of a word in Sε has its exponent between 7/4 and 7/4 + ε, and, no word of Sε has for factor a homomorphic image of another word of Sε.