Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Spin Period of EX Hydrae   We show that the spin period of the white dwarf in the magnetic CV EX Hydrae
represents an equilibrium state in which the corotation radius is comparable
with the distance from the white dwarf to the inner Lagrange point. We also
show that a continuum of spin equilibria exists at which Pspin is significantly
longer than \sim 0.1 Porb. Most systems occupying these equilibrium states
should have orbital periods below the CV period gap, as observed.

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The categories of this paper are: ao-sci
35
The categories of this paper are: mtrl-th
0
The categories of this paper are: hep-ph
29
The categories of this paper are: funct-an
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The categories of this paper are: supr-con
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The categories of this paper are: solv-int
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The categories of this paper are: patt-sol
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The categories of this paper are: stat
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The categories of this paper are: chao-dyn
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The categories of this paper are: adap-org
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The categories of this paper are: q-fin
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The categories of this paper are: q-alg
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The categories of this paper are: quant-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: econ
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The categories of this paper are: math