Let E-Omega(X) be the group of homotopy classes of self-homotopy equivalences of X such that Omega f similar or equal to 1d(Omega X). We prove that epsilon(Omega)(X) is a nilpotent group and that nil epsilon(Omega)(X) less than or equal to cat(X) - 1.
Félix, Y., & Murillo, A. (1998). A bound for the nilpotency of a group of self homotopy equivalences. Proceedings of the American Mathematical Society, 126(2), 625-627. https://doi.org/10.1090/S0002-9939-98-04192-6 (Original work published 1998)