Independent sets in tensor graph powers
β Scribed by Alon, Noga (author);Lubetzky, Eyal (author)
- Publisher
- Wiley-Liss Inc.
- Year
- 2006
- Tongue
- English
- Weight
- 154 KB
- Volume
- 54
- Category
- Article
- ISSN
- 0364-9024
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β¦ Synopsis
Abstract
The tensor product of two graphs, G and H, has a vertex set V(G) Γ V(H) and an edge between (u,v) and (uβ²,vβ²) iff both u uβ² β E(G) and v vβ² β E(H). Let A(G) denote the limit of the independence ratios of tensor powers of G, lim, Ξ±(G^n^)/|V(G^n^)|. This parameter was introduced in [Brown, Nowakowski, Rall, SIAM J Discrete Math 9 (1996), 290β300], where it was shown that A(G) is lower bounded by the vertex expansion ratio of independent sets of G. In this article we study the relation between these parameters further, and ask whether they are in fact equal. We present several families of graphs where equality holds, and discuss the effect the above question has on various open problems related to tensor graph products. Β© 2006 Wiley Periodicals, Inc. J Graph Theory
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