Noncommutative sets of small doubling
Combinatorics
2012-04-04 v2
Abstract
A corollary of Kneser's theorem, one sees that any finite non-empty subset of an abelian group with can be covered by at most translates of a finite group of cardinality at most . Using some arguments of Hamidoune, we establish an analogue in the noncommutative setting. Namely, if is a finite non-empty subset of a nonabelian group such that , then is either contained in a right-coset of a finite group of cardinality at most , or can be covered by at most right-cosets of a finite group of cardinality at most . We also note some connections with some recent work of Sanders and of Petridis.
Cite
@article{arxiv.1106.2267,
title = {Noncommutative sets of small doubling},
author = {Terence Tao},
journal= {arXiv preprint arXiv:1106.2267},
year = {2012}
}
Comments
8 pages, no figures. To appear, European Journal of Combinatorics. This is the final version, incorporating the referee corrections