文摘
In this paper, we give all the solutions \({g,h:\mathbb{R}\to\mathbb{R}}\) (the reals) of the functional equation $$g(x)g(y)-g(x+y)=h(x+y-xy)-h(x)-h(y)+h(xy) \quad(x,y\in\mathbb{R}),$$supposing additionally that h is continuous. This result is in connection with the alienation of the exponential Cauchy equation g(x + y) = g(x)g(y) and the Hosszú equation h(x + y−xy) + h(xy) = h(x) + h(y), namely it turns out that these equations are alien provided that h is continuous. Keywords Cauchy equation Hosszú equation alienation Mathematics Subject Classification Primary 39B22 Secondary 39B72 The research of the first author was supported by the Hungarian Scientific Research Fund (OTKA) Grant NK 111651.