On the growth rates of complexity of threshold languages

Threshold languages, which are the (k/(k–1))+-free languages over k-letter alphabets with k ≥ 5, are the minimal infinite power-free languages according to Dejean's conjecture, which is now proved for all alphabets. We study the growth properties of these languages. On the base of obtained structural properties and computer-assisted studies we conjecture that the growth rate of complexity of the threshold language over k letters tends to a constant $\hat{\alpha}\approx1.242$ as k tends to infinity