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e-Article

The diameter of random Schreier graphs
Document Type
Working Paper
Source
Subject
Mathematics - Combinatorics
Mathematics - Group Theory
Primary 05C89, 20F69
Language
Abstract
We give a combinatorial proof of the following theorem. Let $G$ be any finite group acting transitively on a set of cardinality $n$. If $S \subseteq G$ is a random set of size $k$, with $k \geq (\log n)^{1+\varepsilon}$ for some $\varepsilon >0$, then the diameter of the corresponding Schreier graph is $O(\log_k n)$ with high probability. Except for the implicit constant, this result is the best possible.
Comment: 9 pages