Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An abstract linking theorem applied to indefinite problems via spectral
  properties   An abstract linking result for Cerami sequences is proved without the Cerami
condition. It is applied directly in order to prove the existence of critical
points for a class of indefinite problems in infinite dimensional Hilbert
Spaces. The main applications are given to Hamiltonian systems and Schrodinger
equations. Here spectral properties of the operators are exploited and
hypotheses of monotonicity on the nonlinearities are discarded.

32
The categories of this paper are: atom-ph
26
The categories of this paper are: bayes-an
16
The categories of this paper are: stat
5
The categories of this paper are: gr-qc
35
The categories of this paper are: mtrl-th
23
The categories of this paper are: solv-int
34
The categories of this paper are: chem-ph
19
The categories of this paper are: eess
8
The categories of this paper are: hep-ex
21
The categories of this paper are: adap-org
0
The categories of this paper are: hep-ph
12
The categories of this paper are: nucl-th
4
The categories of this paper are: cond-mat
10
The categories of this paper are: q-bio
9
The categories of this paper are: nlin
31
The categories of this paper are: ao-sci