Abstract
A family of high-degree triangle-free pseudo-random Cayley graphs has been constructed in (Alon, Electro J Combin 1(R12):8, 1994 [2]), motivated by a geometric question of Lovász. These graphs turned out to be useful in tackling a variety of additional extremal problems in Graph Theory and Coding Theory. Here we describe the graphs and their applications, and mention several intriguing related open problems. This is mainly a survey, but it contains several new results as well. One of these is a construction showing that the Lovász \(\theta \)-function of a graph cannot be bounded by any function of its Shannon capacity.
Dedicated to László Lovász, for his seventieth birthday
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Research supported in part by NSF grant DMS-1855464, ISF grant 281/17, GIF grant G-1347-304.6/2016 and the Simons Foundation.
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Alon, N. (2019). Lovász, Vectors, Graphs and Codes. In: Bárány, I., Katona, G., Sali, A. (eds) Building Bridges II. Bolyai Society Mathematical Studies, vol 28. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-662-59204-5_1
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