Hyers–Ulam Stability Constant Research Articles

Integral Transforms and the Hyers–Ulam Stability of Linear Differential Equations with Constant Coefficients

Integral transform methods are a common tool employed to study the Hyers–Ulam stability of differential equations, including Laplace, Kamal, Tarig, Aboodh, Mahgoub, Sawi, Fourier, Shehu, and Elzaki integral transforms. This work provides improved techniques for integral transforms in relation to establishing the Hyers–Ulam stability of differential equations with constant coefficients, utilizing the Kamal transform, where we focus on first- and second-order linear equations. In particular, in this work, we employ the Kamal transform to determine the Hyers–Ulam stability and Hyers–Ulam stability constants for first-order complex constant coefficient differential equations and, for second-order real constant coefficient differential equations, improving previous results obtained by using the Kamal transform. In a section of examples, we compare and contrast our results favorably with those established in the literature using means other than the Kamal transform.

Hyers—Ulam Stability of Second-Order Linear Dynamic Equations on Time Scales

We investigate the Hyers—Ulam stability (HUS) of certain second-order linear constant coefficient dynamic equations on time scales, building on recent results for first-order constant coefficient time-scale equations. In particular, for the case where the roots of the characteristic equation are non-zero real numbers that are positively regressive on the time scale, we establish that the best HUS constant in this case is the reciprocal of the absolute product of these two roots. Conditions for instability are also given.

Best constant for Hyers–Ulam stability of two step sizes linear difference equations

This study deals with the Hyers–Ulam stability (HUS) for the first-order linear difference equations with two alternating step sizes, where the coefficient is allowed to be complex valued. In particular, it turns out that the best HUS constant can be determined by finding an explicit solution to the corresponding inhomogeneous linear equation. Special cases of these results validate previous literature in the field.

Hyers–Ulam stability for quantum equations

We introduce and study the Hyers–Ulam stability (HUS) of a Cayley quantum (q-difference) equation of first order, where the constant coefficient is allowed to range over the complex numbers. In particular, if this coefficient is non-zero, then the quantum equation has Hyers–Ulam stability for certain values of the Cayley parameter, and we establish the best (minimal) HUS constant in terms of the coefficient only, independent of q and the Cayley parameter. If the Cayley parameter equals one half, then there is no Hyers–Ulam stability for any coefficient value in the complex plane.

Hyers–Ulam Stability for Quantum Equations of Euler Type

Many applications using discrete dynamics employ either q-difference equations or h-difference equations. In this work, we introduce and study the Hyers–Ulam stability (HUS) of a quantum (q-difference) equation of Euler type. In particular, we show a direct connection between quantum equations of Euler type and h-difference equations of constant step size h with constant coefficients and an arbitrary integer order. For equation orders greater than two, the h-difference results extend first-order and second-order results found in the literature, and the Euler-type q-difference results are completely novel for any order. In many cases, the best HUS constant is found.

Ulam stability of linear differential equations using Fourier transform

The purpose of this paper is to study the Hyers-Ulam stability and generalized Hyers-Ulam stability of general linear differential equations of $n$th order with constant coefficients by using the Fourier transform method. Moreover, the Hyers-Ulam stability constants are obtained for these differential equations.

Hyers–Ulam stability for a discrete time scale with two step sizes

We clarify the Hyers–Ulam stability (HUS) of certain first-order linear constant coefficient dynamic equations on time scales, in the case of a specific time scale with two alternating step sizes, where the exponential function changes sign. In particular, in the case of HUS, we discuss the HUS constant, and whether a minimal HUS constant can be found.

The Hyers–Ulam stability constant for Chebyshevian Bernstein operators

On a closed bounded interval, a given Extended Chebyshev space which possesses a Bernstein basis generates infinitely many operators of the Bernstein-type. We show that all these operators share the same Hyers–Ulam stability constant. This constant is the maximum, in absolute value, of the Bézier coefficients of the generalised Chebyshev polynomial associated with the given space. We establish an optimality property of these Bernstein operators with respect to the Hyers–Ulam stability constant. Numerical computations of these constants are investigated in two cases: rational and Müntz Bernstein operators, with special emphasis on their behaviour with respect to the concerned interval and to dimension elevation.

On the stability of some positive linear operators from approximation theory

Recently, Popa and Raşa have shown the stability/ instability of some classical operators defined on $$[0,1]$$ and obtained the best constant when the positive linear operators are stable in the sense of Hyers–Ulam. In this paper we show that the Kantorovich–Stancu type operators, King’s operator, Bernstein–Stancu type operators, and Kantorovich–Bernstein–Stancu type operators with shifted knots are Hyers–Ulam stable. Further we find the best Hyers–Ulam stability constants for some of these operators. We also prove that Szász–Mirakjan and Kantorovich–Szász–Mirakjan type operators are unstable in the sense of Hyers and Ulam.

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.

The Hyers–Ulam stability constants of first order linear differential operators

Let X be a complex Banach space, h a complex-valued continuous function on the real line R and T h :C 1( R,X)→C( R,X) the linear differential operator defined by T h u= u′+ hu. We completely determine the Hyers–Ulam stability constant of T h .