A subadditive property of the gamma function

Let Δ = minx 0 Γ (2x)/Γ (x) and α∗ = log 2/ logΔ=−0.946850. . . .We prove that the function x →(Γ (x))α is subadditive on (0,∞) if and only if α∗ α 0.  2003 Elsevier Inc. All rights reserved.