On a new conjecture about super-monochromatic factorisations and ultimate periodicity

Abstract

We study a conjecture linking ultimate periodicity of infnite words to the existence of colorings on finite words avoiding monochromatic factorisation of suffixes, with the extra condition that the ordered concatenation of elements of this factorisation remains monochromatic. This type of results shows the limits of Ramsey theory in the context of combinatorics on words. We show some reductions of the problem and the example of the Zimin word. Using the new notion of consecutive length, we show that words avoiding large squares fulfill the conjecture.