Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Instability for standing waves of nonlinear Klein-Gordon equations via
  mountain-pass arguments   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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The categories of this paper are: physics
7
The categories of this paper are: hep-th
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The categories of this paper are: hep-ex
1
The categories of this paper are: cs
34
The categories of this paper are: chem-ph
35
The categories of this paper are: mtrl-th
0
The categories of this paper are: hep-ph
26
The categories of this paper are: bayes-an
18
The categories of this paper are: econ
31
The categories of this paper are: ao-sci
29
The categories of this paper are: funct-an
15
The categories of this paper are: nucl-ex
25
The categories of this paper are: patt-sol
33
The categories of this paper are: plasm-ph
30
The categories of this paper are: q-alg
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The categories of this paper are: hep-lat