Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: $\epsilon$-isothermic surfaces in pseudo-Euclidean 3-space   In this paper we describe the $\epsilon$-isothermic surfaces in the
pseudo-Euclidean 3-space and we obtain the pseudo-Calapso equation. In
sequence, we classify the Dupin surfaces in pseudo-Euclidean 3-space having
distinct principal curvatures and provide explicit coordinates for such
surfaces. As application of the theory, we give explicit solutions to the
pseudo-Calapso equation.

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The categories of this paper are: astro-ph
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The categories of this paper are: q-bio
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The categories of this paper are: patt-sol
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The categories of this paper are: hep-lat
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The categories of this paper are: nucl-th
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The categories of this paper are: eess
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The categories of this paper are: cond-mat
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The categories of this paper are: alg-geom
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The categories of this paper are: solv-int
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The categories of this paper are: q-alg
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The categories of this paper are: math-ph
29
The categories of this paper are: funct-an
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The categories of this paper are: hep-ex
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The categories of this paper are: quant-ph
0
The categories of this paper are: hep-ph
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The categories of this paper are: chao-dyn