Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ptolemy relations for punctured discs   We construct frieze patterns of type D_N with entries which are numbers of
matchings between vertices and triangles of corresponding triangulations of a
punctured disc. For triangulations corresponding to orientations of the Dynkin
diagram of type D_N, we show that the numbers in the pattern can be interpreted
as specialisations of cluster variables in the corresponding Fomin-Zelevinsky
cluster algebra.

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The categories of this paper are: solv-int
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The categories of this paper are: comp-gas
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The categories of this paper are: hep-lat
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The categories of this paper are: plasm-ph
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The categories of this paper are: q-fin
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The categories of this paper are: cs
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The categories of this paper are: patt-sol
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The categories of this paper are: math-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: eess
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The categories of this paper are: hep-ph
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The categories of this paper are: supr-con
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The categories of this paper are: hep-ex
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The categories of this paper are: hep-th
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The categories of this paper are: stat
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The categories of this paper are: chem-ph