International Mathematics Research Notices Advance Access originally published online on February 28, 2009
International Mathematics Research Notices (2009) 2009:2347-2373, doi:10.1093/imrn/rnp019 published on June 28, 2009
| ||||||||||||||||||||||||||||||||||||||||||||||||||
Geometric Inequalities and Generalized Ricci Bounds in the Heisenberg Group
Institut Fourier BP 74, UMR 5582, Université Grenoble I, 38402 Saint-Martin-d'Hères Cedex, France, and Institute for Applied Mathematics, University of Bonn, Poppelsdorfer Allee 82, 53 115 Bonn, Germany
Correspondence: Correspondence to be sent to: nicolas.juillet{at}ujf-grenoble.fr
We prove that no curvature-dimension bound CD(K,N) holds in any Heisenberg group
. On the contrary, the measure contraction property MCP(0, 2n + 3) holds and is optimal for the dimension 2n + 3. For the nonexistence of a curvature-dimension bound, we prove that the generalized "geodesic" Brunn–Minkowski inequality is false in
. We also show in a new and direct way (and for all
), that the general "multiplicative" Brunn–Minkowski inequality with dimension N > 2n + 1 is false.