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arXiv · 0710.5583

Instability for standing waves of nonlinear Klein-Gordon equations via mountain-pass arguments

Louis Jeanjean·Stefan Le Coz
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Abstract

We introduce mountain-pass type arguments in the context of orbital instability for Klein-Gordon equations. Our aim is to illustrate on two examples how these arguments can be useful to simplify proofs and derive new results of orbital stability/instability. For a power-type nonlinearity, we prove that the ground states of the associated stationary equation are minimizers of the functional "action" on a wide variety of constraints. For a general nonlinearity, we extend to the dimension N=2 the classical instability result for stationary solutions of nonlinear Klein-Gordon equations proved in 1985 by Shatah in dimension N>2.

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Louis Jeanjean, Stefan Le Coz. 2007-10-30. Instability for standing waves of nonlinear Klein-Gordon equations via mountain-pass arguments. https://doi.org/10.1090/s0002-9947-09-04790-4

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