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arXiv · 2011.12031

Frequency theorem for parabolic equations and its relation to inertial manifolds theory

Mikhail Anikushin
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Abstract

We obtain a version of the Frequency Theorem (a theorem on solvability of certain operator inequalities), which allows to construct quadratic Lyapunov functionals for semilinear parabolic equations. We show that the well-known Spectral Gap Condition, which was used in the theory of inertial manifolds by C. Foias, R. Temam and G. R. Sell, is a particular case of some frequency inequality, which arises within the Frequency Theorem. In particular, this allows to construct inertial manifolds for semilinear parabolic equations (including also some non-autonomous problems) in the context of a more general geometric theory developed in our adjacent works. This theory is based on quadratic Lyapunov functionals and generalizes the frequency-domain approach used by R. A. Smith. We also discuss the optimality of frequency inequalities and its relationship with known old and recent results in the field.

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BibTeXRIS

Mikhail Anikushin. 2020-11-24. Frequency theorem for parabolic equations and its relation to inertial manifolds theory. https://doi.org/10.1016/j.jmaa.2021.125454

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