Better Lower Bounds for Shortcut Sets and Additive Spanners via an Improved Alternation Product
Better Lower Bounds for Shortcut Sets and Additive Spanners via an Improved Alternation Product
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通过改进的交替乘积为快捷方式集和附加扳手提供更好的下界
DOI:
10.1137/1.9781611977073.131
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发表时间:
2021
期刊:
影响因子:
--
通讯作者:
Zixuan Xu
中科院分区:
文献类型:
--
作者:
Kevin Lu;V. V. Williams;Nicole Wein;Zixuan Xu
We obtain improved lower bounds for additive spanners, additive emulators, and diameter-reducing shortcut sets. Spanners and emulators are sparse graphs that approximately preserve the distances of a given graph. A shortcut set is a set of edges that when added to a directed graph, decreases its diameter. The previous best known lower bounds for these three structures are given by Huang and Pettie [SWAT 2018]. For $O(n)$-sized spanners, we improve the lower bound on the additive stretch from $\Omega(n^{1/11})$ to $\Omega(n^{2/21})$. For $O(n)$-sized emulators, we improve the lower bound on the additive stretch from $\Omega(n^{1/18})$ to $\Omega(n^{1/16})$. For $O(m)$-sized shortcut sets, we improve the lower bound on the graph diameter from $\Omega(n^{1/11})$ to $\Omega(n^{1/8})$. Our key technical contribution, which is the basis of all of our bounds, is an improvement of a graph product known as an alternation product.
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DOI:
10.1145/3350755.3400222
发表时间:
2020
期刊:
ACM Symposium on Parallelism in Algorithms and Architectures
影响因子:
--
作者:
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通讯作者:
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影响因子:
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DOI:
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发表时间:
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期刊:
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影响因子:
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DOI:
10.1109/focs.2019.00098
发表时间:
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期刊:
Annual Symposium on Foundations of Computer Science (FOCS
影响因子:
--
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