theorem nontrivial_fixed_point_iff {J : ℕ} (hJ : 2 ≤ J) {ρ : ℝ} (hρ : ρ < 1) : 0 < curvatureK J ρ := curvatureK_pos hJ hρ
thesis/CESProofs/Hierarchy/RenormalizationGroup.lean:251
Renormalization Group for CES: