Homological and homotopical higher-order filling functions
arXiv:0805.0584
Abstract
We construct groups in which FV^3(n) != δ^2(n). This construction also leads to groups G_k, k >= 3 for which δ^{k}(n) is not subrecursive.
6 pages, added Lemma 1, to appear in Groups, Geometry, and Dynamics