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Colloquium Mathematics, Professor Rafael Ortega

01 July 2014

Join us for coffee and tea at 15.30 p.m.


Tuesday, July 1st 2014


Professor Rafael Ortega


5161.0293 (Bernoulliborg)



Title: Periodic solutions of the forced pendulum: from existence to stability


Consider the equation $$x''+\beta \sin x=f(t)$$ where $f(t)$ is a periodic forcing. This simple model is a good laboratory to test some global methods in Nonlinear Analysis. Traditionally the existence of periodic solutions is discussed using tools coming from Topology and Calculus of Variations. In this talk we will try to adapt these tools for the study of the stability of these solutions. The results will be of the type "For almost every forcing $f(t)$..." and the notion of set of measure zero in a space of infinite dimensions will play an important role.

Colloquium coordinators are Prof.dr. A.C.D. van Enter (e-mail : and Dr. A.V. Kiselev (e-mail: a.v.kiselev )

Last modified:10 February 2021 2.28 p.m.

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