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A spectral lower bound for the treewidth of a graph and its consequences

โœ Scribed by L.Sunil Chandran; C.R. Subramanian


Publisher
Elsevier Science
Year
2003
Tongue
English
Weight
95 KB
Volume
87
Category
Article
ISSN
0020-0190

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โœฆ Synopsis


We give a lower bound for the treewidth of a graph in terms of the second smallest eigenvalue of its Laplacian matrix. We use this lower bound to show that the treewidth of a d-dimensional hypercube is at least 3

We generalize this result to Hamming graphs. We also observe that every graph G on n vertices, with maximum degree โˆ†

(1) contains an induced cycle (chordless cycle) of length at least 1 + log โˆ† (ยตn/8) (provided G is not acyclic), (2) has a clique minor K h for some h = ((nยต 2 /(โˆ† + 2ยต) 2 ) 1/3 ), where ยต is the second smallest eigenvalue of the Laplacian matrix of G.


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