Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Minimal surfaces in 4-dimensional Lorentzian Damek-Ricci spaces   In this paper we will construct a Weierstrass type representation for minimal
surfaces in 4-dimensional Lorentzian Damek-Ricci spaces and we give some
examples of such surfaces.

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The categories of this paper are: quant-ph
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The categories of this paper are: math-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: stat
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The categories of this paper are: funct-an
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The categories of this paper are: physics
34
The categories of this paper are: chem-ph
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The categories of this paper are: eess
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The categories of this paper are: supr-con
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The categories of this paper are: adap-org
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The categories of this paper are: q-bio
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The categories of this paper are: hep-lat
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The categories of this paper are: ao-sci
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The categories of this paper are: bayes-an
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The categories of this paper are: mtrl-th