Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Faster Algorithm for the Maximum Even Factor Problem   Given a digraph $G = (VG,AG)$, an \emph{even factor} $M \subseteq AG$ is a
subset of arcs that decomposes into a collection of node-disjoint paths and
even cycles. Even factors in digraphs were introduced by Geleen and Cunningham
and generalize path matchings in undirected graphs. Finding an even factor of
maximum cardinality in a general digraph is known to be NP-hard but for the
class of \emph{odd-cycle symmetric} digraphs the problem is polynomially
solvable. So far, the only combinatorial algorithm known for this task is due
to Pap; it has the running time of $O(n^4)$ (hereinafter $n$ stands for the
number of nodes in $G$). In this paper we present a novel \emph{sparse
recovery} technique and devise an $O(n^3 \log n)$-time algorithm for finding a
maximum cardinality even factor in an odd-cycle symmetric digraph.

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The categories of this paper are: astro-ph
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The categories of this paper are: eess
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The categories of this paper are: physics
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The categories of this paper are: nucl-th
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The categories of this paper are: hep-th
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The categories of this paper are: gr-qc
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The categories of this paper are: mtrl-th
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The categories of this paper are: econ
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The categories of this paper are: q-bio
0
The categories of this paper are: hep-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: funct-an
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The categories of this paper are: patt-sol
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The categories of this paper are: alg-geom
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The categories of this paper are: solv-int
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The categories of this paper are: hep-ex