3 citations · 3 across the 6 of their papers we have counts for
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Operator relations characterizing higher-order differential operators
Włodzimierz Fechner, Eszter Gselmann, Aleksandra Świątczak
Let be a positive integer, be a nonnegative integer and be a domain. Further, for all multi-indices , , let us con…
Polynomial equations for additive functions II
Eszter Gselmann, Gergely Kiss
In this sequence of work we investigate polynomial equations of additive functions. We consider the solutions of equation \[ \sum_{i=1}^{n}f_{i}(x^{p_{i}})g_{i}(x)^{q_{i}}= 0 \qqua…
Stability in the class of first order delay differential equations
Eszter Gselmann, Anna Kelemen
The main aim of this paper is the investigation of the stability problem for ordinary delay differential equations. More precisely, we would like to study the following problem. As…
Stability of the entropy equation
Eszter Gselmann
In this paper we prove that the so--called entropy equation, i.e., \[ H\left(x, y, z\right)=H\left(x+y, 0, z\right)+H\left(x, y, 0\right) \] is stable in the sense of Hyers and Ula…