50 citations · 99 across the 19 of their papers we have counts for
22 papers
Best Ulam constants for damped linear oscillators with variable coefficients
Douglas R. Anderson, Masakazu Onitsuka, Donal O'Regan
This study uses an associated Riccati equation to study the Ulam stability of non-autonomous linear differential vector equations that model the damped linear oscillator. In partic…
Best Ulam constants for two-dimensional non-autonomous linear differential systems
Douglas R. Anderson, Masakazu Onitsuka, Donal O'Regan
This study deals with the Ulam stability of non-autonomous linear differential systems without assuming the condition that they admit an exponential dichotomy. In particular, the b…
Hyers-Ulam stability for differential systems with constant coefficient matrix
Douglas R. Anderson, Masakazu Onitsuka
We explore the Hyers-Ulam stability of perturbations for a homogeneous linear differential system with constant coefficient matrix. New necessary and sufficient conditi…
Hyers--Ulam stability for quantum equations
Douglas R. Anderson, Masakazu Onitsuka
We introduce and study the Hyers--Ulam stability (HUS) of a Cayley quantum (-difference) equation of first order, where the constant coefficient is allowed to range over the com…
Best constant for Ulam stability of first-order h-difference equations with periodic coefficient
Douglas R. Anderson, Masakazu Onitsuka, John Michael Rassias
We establish the best (minimum) constant for Ulam stability of first-order linear -difference equations with a periodic coefficient. First, we show Ulam stability and find the U…
A Multi-Valued Logarithm on Time Scales
Douglas R. Anderson, Martin Bohner
A new definition of a multi-valued logarithm on time scales is introduced for delta-differentiable functions that never vanish. This new logarithm arises naturally from the definit…