In the paper we improve some results from 9 concerning the Goła̧b–Schinzel inequality f (x+f (x) y) f (x) f (y) for a continuous unknown function f: R R. We also show some properties of solutions of the generalized inequality f (x+g (x) y) f (x) f (y) for continuous unknown functions f, g: R R provided g f.
Jabłońska et al. (2026) studied this question.