Stable length in stable groups
arXiv:0806.2771
Abstract
We show that the stable commutator length vanishes for certain groups defined as infinite unions of smaller groups. The argument uses a group-theoretic analogue of the Mazur swindle, and goes back to the works of Anderson, Fisher, and Mather on homeomorphism groups.
Dedicated to Shigeyuki Morita on the occasion of his 60th birthday. To appear in Groups of Diffeomorphisms (Mathematical Society of Japan)