Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Effects of a deformation of a star on the gravitational lensing   We study analytically a gravitational lens due to a deformed star, which is
modeled by using a monopole and a quadrupole moment. Positions of the images
are discussed for a source on the principal axis. We present explicit
expressions for the lens equation for this gravitational lens as a single real
tenth-order algebraic equation. Furthermore, we compute an expression for the
caustics as a discriminant for the polynomial. Another simple parametric
representation of the caustics is also presented in a more tractable form. A
simple expression for the critical curves is obtained to clarify a topological
feature of the critical curves; the curves are simply connected if and only if
the distortion is sufficiently large.

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The categories of this paper are: acc-phys
32
The categories of this paper are: atom-ph
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The categories of this paper are: solv-int
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The categories of this paper are: chao-dyn
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The categories of this paper are: dg-ga
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The categories of this paper are: eess
35
The categories of this paper are: mtrl-th
12
The categories of this paper are: nucl-th
0
The categories of this paper are: hep-ph
14
The categories of this paper are: math-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: cmp-lg
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The categories of this paper are: hep-th
2
The categories of this paper are: math
34
The categories of this paper are: chem-ph
27
The categories of this paper are: comp-gas