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Acta Mathematica Vietnamica

Unstable Manifolds for Partial Neutral Differential Equations and Admissibility of Function Spaces

icon-email Thieu Huy Nguyen , Van Bang Pham

Abstract

We prove the existence and attraction property of an unstable manifold for solutions to the partial neutral functional differential equation of the form {tFut=B(t)Fut+Φ(t,ut),ts; t,sR,us=ϕC:=C([r,0],X) under the conditions that the family of linear operators (B(t))tR defined on a Banach space X generates the evolution family (U(t,s))ts having an exponential dichotomy on the whole line R, the difference operator F:CX is bounded and linear, and the nonlinear delay operator Φ satisfies the φ-Lipschitz condition, i.e., Φ(t,ϕ)Φ(t,ψ)ϕ(t)ϕψC for ϕ, ψC, where φ() belongs to an admissible function space defined on R. Our main method is based on Lyapunov-Perron’s equations combined with the admissibility of function spaces and the technique of choosing F-induced trajectories.