2016/05/12 by Tao, Jing
#20E05 #20F12 #20F65 #FOS: Mathematics #Group Theory (math.GR)
paper · doi:10.48550/arxiv.1605.03682
We find homogeneous counting quasimorphisms that are effective at seeing chains in a free group F. As corollary, we derive that if a group G has an index-d free subgroup, then every element g in G either has stable commutator length at least 1/8d or some power of g is conjugate to its inverse. We also show that for a finitely-generated free group F, there is a countable basis for the real vector space of homogeneous quasimorphisms on F.