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» A Combinatorial Proof of Kneser's Conjecture
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JCT
2007
97views more  JCT 2007»
15 years 6 months ago
What power of two divides a weighted Catalan number?
Given a sequence of integers b = (b0,b1,b2,...) one gives a Dyck path P of length 2n the weight wt(P) = bh1 bh2 ···bhn , where hi is the height of the ith ascent of P. The corr...
Alexander Postnikov, Bruce E. Sagan
STACS
2009
Springer
16 years 24 days ago
Hardness and Algorithms for Rainbow Connectivity
An edge-colored graph G is rainbow connected if any two vertices are connected by a path whose edges have distinct colors. The rainbow connectivity of a connected graph G, denoted ...
Sourav Chakraborty, Eldar Fischer, Arie Matsliah, ...
DM
2008
103views more  DM 2008»
15 years 6 months ago
A note on lattice chains and Delannoy numbers
Fix nonnegative integers n1, . . . , nd and let L denote the lattice of integer points (a1, . . . , ad) Zd satisfying 0 ai ni for 1 i d. Let L be partially ordered by the usua...
John S. Caughman IV, Clifford R. Haithcock, J. J. ...
FOCS
2009
IEEE
16 years 24 days ago
Distance Oracles for Sparse Graphs
Abstract— Thorup and Zwick, in their seminal work, introduced the approximate distance oracle, which is a data structure that answers distance queries in a graph. For any integer...
Christian Sommer 0002, Elad Verbin, Wei Yu
ECCC
2008
168views more  ECCC 2008»
15 years 6 months ago
Algebrization: A New Barrier in Complexity Theory
Any proof of P = NP will have to overcome two barriers: relativization and natural proofs. Yet over the last decade, we have seen circuit lower bounds (for example, that PP does n...
Scott Aaronson, Avi Wigderson