fact: Hypothesis eps_gt0 : 0 < epsilon.
imports: Coq(Reals ZArith Psatz Fourier_util) Flocq(Raux) Coquelicot(Coquelicot AutoDerive) mathcomp.ssreflect(ssreflect ssrfun ssrbool ssrnat bigop) Stdlib Coquelicot Xreal Interval