Roughness of exponential dichotomy under unbounded perturbation in linear partial functional differential equations

Fuente: arXiv
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Main Authors: Bui, Xuan-Quang, Van Minh, Nguyen
Format: Preprint
Published: 2023
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author Bui, Xuan-Quang
Van Minh, Nguyen
author_facet Bui, Xuan-Quang
Van Minh, Nguyen
contents This paper is concerned with the roughness of exponential dichotomies under unbounded perturbations of a class of linear partial functional differential equations \begin{equation}\label{pfde-000-1star} u'(t)=Au(t)+Bu_t, \end{equation} where $A$ is a linear operator on a Banach space $\mathbb{X}$ and $B$ is a linear operator from $C([-r,0],\mathbb{X})$ into $\mathbb{X}$, where $r>0$ is a given constant. To quantify the size of unbounded perturbations, we introduce the \textit{Yosida distance} between linear operators $U$ and $V$, defined by $d_Y(U,V):=\limsup_{μ\to +\infty} \| U_μ-V_μ\|$, where $U_μ$ and $V_μ$ are the Yosida approximations of $U$ and $V$, respectively. We show that if $d_Y(A, A_1)$ and $d_Y(B, B_1)$ are sufficiently small, then the perturbed equation \begin{equation}\label{pfde-000-2star} u'(t)=A_1u(t)+B_1u_t \end{equation} also admits an exponential dichotomy whenever \eqref{pfde-000-1star} admits one. The proofs are based on estimates of the Yosida distance between the generators of the solution semigroups associated with \eqref{pfde-000-1star} and \eqref{pfde-000-2star} in the phase space $C([-r,0],\mathbb{X})$, without assuming any relation between their domains.
format Preprint
id arxiv_https___arxiv_org_abs_2310_04873
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Roughness of exponential dichotomy under unbounded perturbation in linear partial functional differential equations
Bui, Xuan-Quang
Van Minh, Nguyen
Dynamical Systems
34G10, 37D10, 34D20, 34C45, 34D09
This paper is concerned with the roughness of exponential dichotomies under unbounded perturbations of a class of linear partial functional differential equations \begin{equation}\label{pfde-000-1star} u'(t)=Au(t)+Bu_t, \end{equation} where $A$ is a linear operator on a Banach space $\mathbb{X}$ and $B$ is a linear operator from $C([-r,0],\mathbb{X})$ into $\mathbb{X}$, where $r>0$ is a given constant. To quantify the size of unbounded perturbations, we introduce the \textit{Yosida distance} between linear operators $U$ and $V$, defined by $d_Y(U,V):=\limsup_{μ\to +\infty} \| U_μ-V_μ\|$, where $U_μ$ and $V_μ$ are the Yosida approximations of $U$ and $V$, respectively. We show that if $d_Y(A, A_1)$ and $d_Y(B, B_1)$ are sufficiently small, then the perturbed equation \begin{equation}\label{pfde-000-2star} u'(t)=A_1u(t)+B_1u_t \end{equation} also admits an exponential dichotomy whenever \eqref{pfde-000-1star} admits one. The proofs are based on estimates of the Yosida distance between the generators of the solution semigroups associated with \eqref{pfde-000-1star} and \eqref{pfde-000-2star} in the phase space $C([-r,0],\mathbb{X})$, without assuming any relation between their domains.
title Roughness of exponential dichotomy under unbounded perturbation in linear partial functional differential equations
topic Dynamical Systems
34G10, 37D10, 34D20, 34C45, 34D09
url https://arxiv.org/abs/2310.04873