We provide a counterexample to a lemma used in a recent tentative improvement
of the the Pin-Frankl bound for synchronizing automata. This example naturally
leads us to formulate an open question, whose answer could fix the line of
proof, and improve the bound.Comment: Short note presenting a counterexample and the resulting open
  questio

Gonze, François

Jungers, Raphaël M.

Trahtman, A. N.