Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Prime Labeling of Ladders   A prime labeling of a graph with $n$ vertices is a labeling of its vertices
with distinct integers from $\{1, 2,\ldots , n\}$ in such a way that the labels
of any two adjacent vertices are relatively prime. T. Varkey conjectured that
ladder graphs have a prime labeling. We prove this conjecture.

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The categories of this paper are: econ
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The categories of this paper are: eess
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The categories of this paper are: q-bio
3
The categories of this paper are: physics
1
The categories of this paper are: cs
4
The categories of this paper are: cond-mat
8
The categories of this paper are: hep-ex
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The categories of this paper are: chao-dyn
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The categories of this paper are: funct-an
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The categories of this paper are: alg-geom
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The categories of this paper are: comp-gas
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The categories of this paper are: hep-ph
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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: acc-phys
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The categories of this paper are: plasm-ph