Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Hermitian structures defined by linear electromagnetic constitutive laws   It is demonstrated that when the bundle of 2-forms on a four-dimensional
manifold M admits an almost-complex structure any choice of "real + imaginary"
subspace decomposition of the bundle defines a conjugation map, as well as a
Hermitian structure for the bundle. When the almost-complex structure comes
from a linear electromagnetic constitutive law, the real and imaginary parts of
the Hermitian structure are then shown to represent the Hamiltonian for an
anisotropic three-dimensional electromagnetic oscillator at each point of M and
a symplectic structure for each fiber. The complex form of the oscillator
equations is also definable in terms of the geometric structures that were
introduced.

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The categories of this paper are: q-alg
33
The categories of this paper are: plasm-ph
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The categories of this paper are: ao-sci
21
The categories of this paper are: adap-org
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The categories of this paper are: acc-phys
24
The categories of this paper are: dg-ga
18
The categories of this paper are: econ
1
The categories of this paper are: cs
34
The categories of this paper are: chem-ph
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The categories of this paper are: supr-con
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The categories of this paper are: comp-gas
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The categories of this paper are: bayes-an
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The categories of this paper are: mtrl-th
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The categories of this paper are: q-fin
3
The categories of this paper are: physics
16
The categories of this paper are: stat