Functional equations satisfied by additive functions have a special interest not only in the
theory of functional equations, but also in the theory of (commutative) algebra because the …

We consider quadratic functions f that satisfy the additional equation y 2 f (x)= x 2 f (y) for the
pairs (x, y) ∈ R^ 2 (x, y)∈ R 2 that fulfill the condition P (x, y)= 0 for some fixed polynomial P …

In 1990, Benz asked whether a real additive map** satisfying xf (y)= yf (x) xf (y)= yf (x) for
all points (x, y) on the unit circle must be linear. In 2005, Boros and Erdei showed that it must …

APPROXIMATE DERIVATIONS OF ORDER n Page 1 Acta Math. Hungar. DOI: 0
APPROXIMATE DERIVATIONS OF ORDER n E. GSELMANN * Institute of Mathematics …

The main purpose of this work is to characterize derivations through functional equations.
This work consists of five chapters. In the first one, we summarize the most important notions …

The purpose of this paper is to introduce the notion of a generalized derivation which
derivates a prescribed family of smooth vector-valued functions of several variables. The …

The purpose of this paper is to show that functions that derivate the two-variable product
function and one of the exponential, trigonometric or hyperbolic functions are also standard …

The main aim of this note is to provide sufficient conditions for an additive function to be a
real derivation. Among others the following implication will be verified: Assume that ξ: R→ R …

In this PhD dissertation we study monomial functions f, g: R→ R of degree n∈ N, n≥ 2
which satisfy the conditional equation y nf (x)= x nf (y) or y nf (x)= x ng (y) for all points (x, y) …

We continue the study of additive functions fk: R→ F (1≤ k≤ n) linked by an equation of the
form∑ nk= 1 pk (x) fk (qk (x))= 0, where the pk and qk are polynomials, R is an integral …