On Hyers–Ulam stability of generalized linear functional equation and its induced Hyers–Ulam programming problem

We propose a new approach called Hyers–Ulam programming to discriminate whether a generalized linear functional equation, with the form \({\sum_{i=1}^m L_if(\sum_{j=1}^n a_{ij}x_j) = 0}\) for functions from a normed space into a Banach space, has the Hyers–Ulam stability or not. Our main result is that if the induced Hyers–Ulam programming has a solution, then the corresponding functional equation possesses the Hyers–Ulam stability.     

Hyers–Ulam stability of hypergeometric differential equations

Aequationes mathematicae - In the present paper by applying the series method we prove the Hyers–Ulam stability of the homogeneous hypergeometric differential equation in a subclass of...     

On Hyers–Ulam stability of two functional equations in non-Archimedean spaces

In this paper we prove, using the fixed point method, the generalized Hyers–Ulam stability of two functional equations in complete non-Archimedean normed spaces. One of these equations characterizes multi-Cauchy–Jensen mappings, and the other gives a characterization of multi-additive-quadratic mappings.     

On the best constant in Hyers–Ulam stability of some positive linear operators

We obtain the infimum of the Hyers–Ulam stability constants for Stancu, Bernstein and Kantorovich operators and prove that in a class of certain positive linear operators this infimum for Bernstein operator has a minimality property.     

On a Jensen-cubic functional equation and its Hyers–Ulam stability

In this paper, we obtain the general solution and stability of the Jensen-cubic functional equation f((x₁+x₂)/2, 2y₁+y₂)+f((x₁+x₂)/2, 2y₁-y₂) = f(x₁, y₁+y₂)+f(x₁, y₁-y₂)+6f(x₁, y₁)+f(x₂, y₁+y₂)+f(x₂, y₁-y₂)+6f(x₂, y₁).     

Hyers–Ulam stability of Euler’s equation

We prove that Euler’s equation $x_1\frac{?u}{?x_1}+x_2\frac{?u}{?x_2}+?+x_n\frac{?u}{?x_n}=\alpha u$, characterising homogeneous functions, is stable in Hyers–Ulam sense if and only if $\alpha \in \mathbb{R}?\left\{0\right\}$.     

Hyers–Ulam stability of derivations and linear functions

In this paper the following implication is verified for certain basic algebraic curves: if the additive real function f approximately (i.e., with a bounded error) satisfies the derivation rule along the graph of the algebraic curve in consideration, then f can be represented as the sum of a derivation and a linear function. When, instead of the additivity of f, it is assumed that, in addition, the Cauchy difference of f is bounded, a stability theorem is obtained for such characterizations of derivations.     

Hyers–Ulam stability of Sahoo–Riedel’s point

In this paper, we construct a counter example to show that “Theorem” of Hyers–Ulam Stability of Flett’s Point in [M. Das, T. Riedel, P.K. Sahoo, Hyers-Ulam stability of Flett’s points, Applied Mathematics Letters. 16 (3) (2003), 269–271] is incorrect. At the same time, we give the correct theorem and generalize it.     

Ulam–Hyers–Mittag-Leffler stability of fractional-order delay differential equations

In this paper, we first prove two existence and uniqueness results for fractional-order delay differential equation with respect to Chebyshev and Bielecki norms. Secondly, we prove the above equation is Ulam–Hyers–Mittag-Leffler stable on a compact interval. Finally, two examples are also provided to illustrate our results.     

The properties of functional inclusions and Hyers–Ulam stability

We prove that a set-valued function satisfying some functional inclusions admits, in appropriate conditions, a unique selection satisfying the corresponding functional equation. As a consequence we obtain the result on the Hyers–Ulam stability of that functional equation.     

Fixed points of a mapping and Hyers–Ulam stability

We show that many general results on Hyers–Ulam stability of some functional equations in a single variable follow immediately from a simple fixed point theorem. The theorem is formulated for self-maps of some subsets of the space of functions from a nonempty set into the set of reals. We also give some applications of that theorem, e.g., in investigations of solutions of some difference equations and functional inequalities.     

Hyers–Ulam stability of a first order partial differential equation

We prove that the existence of a global prime integral leads, in appropriate conditions, to the Hyers–Ulam stability of a linear partial differential equation of first order.     

Hyers–Ulam stability of linear partial differential equations of first order

In this work, we will prove the Hyers–Ulam stability of linear partial differential equations of first order.