Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: A Flat Strip Theorem for Ptolemaic Spaces   We prove a flat strip theorem for 2-dimensional ptolemaic spaces.

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The categories of this paper are: hep-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: hep-lat
26
The categories of this paper are: bayes-an
12
The categories of this paper are: nucl-th
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-th
37
The categories of this paper are: supr-con
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The categories of this paper are: alg-geom
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The categories of this paper are: acc-phys
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The categories of this paper are: econ
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The categories of this paper are: physics
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The categories of this paper are: nlin
33
The categories of this paper are: plasm-ph
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The categories of this paper are: cs
30
The categories of this paper are: q-alg