Steven Kelk,
Leo van Iersel,
Nela Lekic,
Simone Linz,
Celine Scornavacca and
Leen Stougie. Cycle killer... qu'est-ce que c'est? On the comparative approximability of hybridization number and directed feedback vertex set. In SIDMA, Vol. 26(4):1635-1656, 2012. Keywords: agreement forest, approximation, explicit network, from rooted trees, minimum number, phylogenetic network, phylogeny, Program CycleKiller, reconstruction. Note: http://arxiv.org/abs/1112.5359, about the title.
Toggle abstract
"We show that the problem of computing the hybridization number of two rooted binary phylogenetic trees on the same set of taxa X has a constant factor polynomial-time approximation if and only if the problem of computing a minimum-size feedback vertex set in a directed graph (DFVS) has a constant factor polynomial-time approximation. The latter problem, which asks for a minimum number of vertices to be removed from a directed graph to transform it into a directed acyclic graph, is one of the problems in Karp's seminal 1972 list of 21 NP-complete problems. Despite considerable attention from the combinatorial optimization community, it remains to this day unknown whether a constant factor polynomial-time approximation exists for DFVS. Our result thus places the (in)approximability of hybridization number in a much broader complexity context, and as a consequence we obtain that it inherits inapproximability results from the problem Vertex Cover. On the positive side, we use results from the DFVS literature to give an O(log r log log r) approximation for the hybridization number where r is the correct value. Copyright © by SIAM."
@Article{KILSS2012,
AUTHOR = {Kelk, Steven and van Iersel, Leo and Lekic, Nela and Linz, Simone and Scornavacca, Celine and Stougie, Leen},
TITLE = {Cycle killer... qu'est-ce que c'est? On the comparative approximability of hybridization number and directed feedback vertex set},
YEAR = {2012},
JOURNAL = {SIDMA},
VOLUME = {26},
NUMBER = {4},
PAGES = {1635-1656},
URL = {http://dx.doi.org/10.1137/120864350},
NOTE = { http://arxiv.org/abs/1112.5359, about the title},
KEYWORDS = {agreement forest, approximation, explicit network, from rooted trees, minimum number, phylogenetic network, phylogeny, Program CycleKiller, reconstruction} }
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