Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Propagation of waves in metallic photonic crystals at low frequencies
  and some theoretical aspects of left-handed materials   An analytical theory of low frequency electromagnetic waves in metallic
photonic crystals with a small volume fraction of a metal is presented. The
evidence of the existence of such waves has been found recently via experiments
and computations. We have obtained an exact dispersion equation for omega (k)
and studied the cutoff frequency omega_0 = omega(0) as a function of parameters
of the photonic crystal. An analytical expression for the permittivity epsilon
is calculated. It is shown, that if the crystal is embedded into a medium with
negative mu, it has no propagating modes at any frequency. Thus, such a
compound system is not a left-handed material (LHM). The recent experimental
results on the LHM are discussed.

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The categories of this paper are: math
30
The categories of this paper are: q-alg
22
The categories of this paper are: chao-dyn
3
The categories of this paper are: physics
28
The categories of this paper are: alg-geom
26
The categories of this paper are: bayes-an
18
The categories of this paper are: econ
21
The categories of this paper are: adap-org
37
The categories of this paper are: supr-con
19
The categories of this paper are: eess
34
The categories of this paper are: chem-ph
23
The categories of this paper are: solv-int
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-ex
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The categories of this paper are: q-bio
7
The categories of this paper are: hep-th