Stability of functional inequality in digital metric space.

In the present article, the Hyers–Ulam stability of the following inequality is analyzed: 0.1 { d (f (ı + ȷ) , (f (ı) + f (ȷ))) ≤ d (ρ 1 ((f (ı + ȷ) + f (ı − ȷ) , 2 f (ı))) d (f (ı + ȷ) , (f (ı) + f (ȷ))) ≤ + d (ρ 2 (2 f (ı + ȷ 2) , (f (ı) + f (ȷ)))) in the setting of digital metric space, where ρ 1 and ρ 2 are fixed nonzero complex numbers with 1 > 2 | ρ 1 | + | ρ 2 | by using fixed point and direct approach. [ABSTRACT FROM AUTHOR]