Twice-ramanujan sparsifiers

By Joshua D. Batson, Daniel A. Spielman, Nikhil Srivastava. Symposium on the Theory of Computing, 2008

580 citations recorded by the source corpus.

We prove that every graph has a spectral sparsifier with a number of edges linear in its number of vertices. As linear-sized spectral sparsifiers of complete graphs are expanders, our sparsifiers of arbitrary graphs can be viewed as generalizations of expander graphs. In particular, we prove that for every d > 1 and every undirected, weighted graph G = (V,E,w) on n vertices, there exists a weighted graph H=(V,F,~{w}) with at most ⌈d(n-1)⌉ edges such that for every x ∈ R<sup>V</sup>, [x<sup>T</sup> L<sub>G</sub> x ≤ x<sup>T</sup> L<sub>H</sub> x ≤ ((d+1+2√d)/(d+1-2√d)) • x<sup>T</sup> L<sub>G</sub> x] where L<sub>G</sub> and L<sub>H</sub> are the Laplacian matrices of G and H, respectively. Thus, H approximates G spectrally at least as well as a Ramanujan expander with dn/2 edges approximates the complete graph. We give an elementary deterministic polynomial time algorithm for constructing H.

Subfields: Computational Theory and Mathematics, Discrete Mathematics and Combinatorics, Geometry and Topology

View Paper: https://www.semanticscholar.org/paper/f1a2ec7363fbdfff3e84a88d2401d1862e3ef146

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The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Computational Theory and Mathematics

  1. David P. Woodruff
  2. Dan Feldman
  3. Daniel A. Spielman
  4. Nikhil Srivastava
  5. Peilin Zhong
  6. Shang-Hua Teng
  7. Adam W. Marcus
  8. Andrew McGregor

In Discrete Mathematics and Combinatorics

  1. Adam W. Marcus
  2. David P. Woodruff
  3. Daniel A. Spielman
  4. Roman Vershynin
  5. Nikhil Srivastava
  6. Garving K. Luli
  7. Arie Israel
  8. Dan Feldman

In Geometry and Topology

  1. David P. Woodruff
  2. Daniel A. Spielman
  3. Nikhil Srivastava
  4. Adam W. Marcus
  5. Dan Feldman
  6. Roman Vershynin
  7. Garving K. Luli
  8. Arie Israel

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