Smoothness of linearization by mixing parameters of dichotomy, bounded growth and perturbation
Álvaro Castañeda, Ignacio Huerta, Gonzalo Robledo
TL;DR
The paper addresses the smoothness of the global, time-parametrized topological conjugacy between a linear nonautonomous system with a nonuniform exponential dichotomy and a quasilinear perturbation. It employs a Green function framework and a parameterized Banach-space setup to construct explicit conjugacy maps $H$ and $G$, proving the existence of a topological conjugacy under a set of conditions that couple dichotomy, bounded growth, and perturbation data. The authors then establish differentiability of the conjugacy and provide a diffeomorphism result on a finite interval by leveraging additional regularity assumptions and Plastock's criterion. The work extends prior results by allowing nonuniform growth and unbounded perturbations, offering explicit parameter relations that widen the smoothness interval and providing a detailed comparison with Jara’s results. This contributes to a more versatile understanding of nonlinear linearization for nonautonomous systems with nontrivial projectors and nonuniform dynamics, with potential implications for global linearization techniques in nonuniform settings.
Abstract
We study the smoothness properties of a global and nonautonomous topological conjugacy between a linear system and a quasilinear perturbation. The linear system exhibits a nonuniform exponential dichotomy with a nontrivial projector and nonuniform bounded growth property. Additionally, the quasilinear perturbation is dominated by an increasing exponential function. Emphasis is placed on employing a set of parameters to describe the conditions of dichotomy, bounded growth and quasilinear perturbations. Finally, we prove that modifying these conditions enables us to achieve a broader smoothness interval.
