Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: How Not to Characterize Planar-emulable Graphs   We investigate the question of which graphs have planar emulators (a
locally-surjective homomorphism from some finite planar graph) -- a problem
raised already in Fellows' thesis (1985) and conceptually related to the better
known planar cover conjecture by Negami (1986). For over two decades, the
planar emulator problem lived poorly in a shadow of Negami's conjecture--which
is still open--as the two were considered equivalent. But, in the end of 2008,
a surprising construction by Rieck and Yamashita falsified the natural "planar
emulator conjecture", and thus opened a whole new research field. We present
further results and constructions which show how far the planar-emulability
concept is from planar-coverability, and that the traditional idea of likening
it to projective embeddability is actually very out-of-place. We also present
several positive partial characterizations of planar-emulable graphs.

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The categories of this paper are: adap-org
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The categories of this paper are: gr-qc
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The categories of this paper are: ao-sci
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The categories of this paper are: patt-sol
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The categories of this paper are: quant-ph
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The categories of this paper are: econ
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The categories of this paper are: comp-gas
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The categories of this paper are: atom-ph
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The categories of this paper are: q-bio
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The categories of this paper are: math-ph
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The categories of this paper are: math
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The categories of this paper are: supr-con
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The categories of this paper are: cmp-lg
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The categories of this paper are: funct-an
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The categories of this paper are: nucl-ex
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The categories of this paper are: chao-dyn