On the stability of generalized gamma functional equation

We obtain the Hyers-Ulam stability and modified Hyers-Ulam stability for the equations of the form g(x+p)= ϕ(x)g(x) in the following settings: |g(x+p)−ϕ(x)g(x)| ≤ δ, |g(x+p)−ϕ(x)g(x) |≤ φ(x), |(g(x + p)/ϕ(x)g(x))−1 |≤ ψ(x). As a consequence we obtain the stability theorems for the gamma functional equation.