Uniformly convex functions on Banach Spaces

Given a Banach space (Χ,∥ · ∥), we study the connection between uniformly convex functions f : Χ → R bounded above by ∥ · ∥ᵖ and the existence of norms on X with moduli of convexity of power type. In particular, we show that there exists a uniformly convex function f : Χ → ℝ bounded above by ∥ · ∥² if and only if Χ admits an equivalent norm with modulus of convexity of power type 2.