Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Cyclic and Linear Graph Partitions and Normal Ordering   The Stirling number of a simple graph is the number of partitions of its
vertex set into a specific number of non-empty independent sets. In 2015,
Engbers et al. showed that the coefficients in the normal ordering of a word
$w$ in the alphabet $\{x,D\}$ subject to the relation $Dx=xD+1$ are equal to
the Stirling number of certain graphs constructed from $w$. In this paper, we
introduce graphical versions of the Stirling numbers of the first kind and the
Lah numbers and show how they occur as coefficients in other normal ordering
settings. Identities involving their $q$-analogues are also obtained.

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The categories of this paper are: hep-th
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The categories of this paper are: atom-ph
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The categories of this paper are: q-alg
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The categories of this paper are: comp-gas
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The categories of this paper are: hep-ex
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The categories of this paper are: adap-org
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The categories of this paper are: hep-lat
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The categories of this paper are: hep-ph
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The categories of this paper are: econ
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The categories of this paper are: cmp-lg
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The categories of this paper are: physics
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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: astro-ph
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The categories of this paper are: q-bio
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The categories of this paper are: ao-sci