Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Geodetic Line at Constant Altitude above the Ellipsoid   The two-dimensional surface of a bi-axial ellipsoid is characterized by the
lengths of its major and minor axes. Longitude and latitude span an angular
coordinate system across. We consider the egg-shaped surface of constant
altitude above (or below) the ellipsoid surface, and compute the geodetic lines
- lines of minimum Euclidean length - within this surface which connect two
points of fixed coordinates. This addresses the common "inverse" problem of
geodesics generalized to non-zero elevations. The system of differential
equations which couples the two angular coordinates along the trajectory is
reduced to a single integral, which is handled by Taylor expansion up to fourth
power in the eccentricity.

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The categories of this paper are: comp-gas
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The categories of this paper are: q-bio
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The categories of this paper are: hep-ex
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The categories of this paper are: cond-mat
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The categories of this paper are: chem-ph
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The categories of this paper are: astro-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: nlin
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The categories of this paper are: mtrl-th
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The categories of this paper are: physics
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The categories of this paper are: adap-org
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The categories of this paper are: hep-th
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The categories of this paper are: nucl-th
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The categories of this paper are: acc-phys
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The categories of this paper are: atom-ph
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The categories of this paper are: alg-geom