Coarse Differentiation and Multi-flows in Planar Graphs
Coarse Differentiation and Multi-flows in Planar Graphs
复制标题
平面图中的粗微分和多流
DOI:
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发表时间:
2007
期刊:
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通讯作者:
P. Raghavendra
中科院分区:
文献类型:
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作者:
James R. Lee;P. Raghavendra
AbstractWe show that the multi-commodity max-flow/min-cut gap for series-parallel graphs can be as bad as 2, matching a recent upper bound (Chakrabarti et al. in 49th Annual Symposium on Foundations of Computer Science, pp. 761–770, 2008) for this class, and resolving one side of a conjecture of Gupta, Newman, Rabinovich, and Sinclair.This also improves the largest known gap for planar graphs from
$frac{3}{2}$
to 2, yielding the first lower bound that does not follow from elementary calculations. Our approach uses the coarse differentiation method of Eskin, Fisher, and Whyte in order to lower bound the distortion for embedding a particular family of shortest-path metrics into L1.