Displaying similar documents to “On functions with the Cauchy difference bounded by a functional. II.”

On the inhomogeneous Cauchy functional equation.

István Fenyö, Gian Luigi Forti (1981)

Stochastica

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In this note we solve the inhomogeneous Cauchy functional equation f(x+y) - f(x) - f(y) = d(x,y), x,y belonging to R, in the case where d is bounded.

On Functions with the Cauchy Difference Bounded by a Functional

Włodzimierz Fechner (2004)

Bulletin of the Polish Academy of Sciences. Mathematics

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K. Baron and Z. Kominek [2] have studied the functional inequality f(x+y) - f(x) - f(y) ≥ ϕ (x,y), x, y ∈ X, under the assumptions that X is a real linear space, ϕ is homogeneous with respect to the second variable and f satisfies certain regularity conditions. In particular, they have shown that ϕ is bilinear and symmetric and f has a representation of the form f(x) = ½ ϕ(x,x) + L(x) for x ∈ X, where L is a linear function. The purpose of...

An existence and stability theorem for a class of functional equations.

Gian Luigi Forti (1980)

Stochastica

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Consider the class of functional equations g[F(x,y)] = H[g(x),g(y)], where g: E --> X, f: E x E --> E, H: X x X --> X, E is a set and (X,d) is a complete metric space. In this paper we prove that, under suitable hypotheses on F, H and ∂(x,y), the existence of a solution of the functional inequality d(f[F(x,y)],H[f(x),f(y)]) ≤ ∂(x,y), implies the existence of a solution of the above equation.