fact: Definition gamma20 x t := 1/(2*c) * RInt (fun tau => Derive (fun u => f u tau) (x + c * (t - tau)) - Derive (fun u => f u tau) (x - c * (t - tau))) 0 t.
imports: Coq(Reals ssreflect) Coquelicot(Rcomplements Derive RInt Hierarchy Derive_2d AutoDerive)