We characterize Carnot groups admitting a 1-quasiconformal metric inversion
as the Lie groups of Heisenberg type whose Lie algebras satisfy the
J2-condition, thus characterizing a special case of inversion invariant
bi-Lipschitz homogeneity. A more general characterization of inversion
invariant bi-Lipschitz homogeneity for certain non-fractal metric spaces is
also provided.Comment: 10 pages. Revised version in which the proof of Theorem 1.1 is
clarifie