Lrzt G = (V, 0 be a ttlock :.>f order n, different from Kn. Let ~FI = min {d(x) + d(y): n then G contains a cycle of length at least m. 1. Introductlion and notatio e discuss only finite undirected graphs withsLc loops and multiple edges. We p:rosye the main theorem d show how Qre's th -orem [ 3.1 o
A spectral lower bound for the treewidth of a graph and its consequences
โ 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
No coin nor oath required. For personal study only.
โฆ 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 โ
(1) contains an induced cycle (chordless cycle) of length at least 1 + log โ (ยตn/8) (provided G is not acyclic), (2) has a clique minor K h for some h = ((nยต 2 /(โ + 2ยต) 2 ) 1/3 ), where ยต is the second smallest eigenvalue of the Laplacian matrix of G.
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