Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the mean curvature of a unit vector field   We present an explicit formula for the mean curvature of a unit vector field
on a Riemannian manifold, using a special but natural frame. As applications,
we treat some known and new examples of minimal unit vector fields. We also
give an example of a vector field of constant mean curvature on the Lobachevsky
$(n+1)$ space.

27
The categories of this paper are: comp-gas
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The categories of this paper are: eess
18
The categories of this paper are: econ
29
The categories of this paper are: funct-an
25
The categories of this paper are: patt-sol
6
The categories of this paper are: astro-ph
34
The categories of this paper are: chem-ph
35
The categories of this paper are: mtrl-th
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The categories of this paper are: bayes-an
7
The categories of this paper are: hep-th
14
The categories of this paper are: math-ph
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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: alg-geom
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg