This paper gives an alternate, elementary proof of a result of Magnani: maps between Carnot groups that preserve horizontal curves and are continuously differential in horizontal directions in the Euclidean sense are continuously Pansu differentiable. This proof contains primarily Euclidean arguments and also reproves a version of Magnani's mean value estimate for continuously Pansu differentiable maps.
| Citation: |
| [1] |
A. Bonfiglioli, E. Lanconelli and F. Uguzzoni, Stratified Lie Groups and Potential Theory for their Sub-LAplacians, Springer Monographs in Mathematics, Springer, Berlin, 2007.
|
| [2] |
V. Chousionis, S. Li and S. Zimmerman, Singular integrals on $C^{1, \alpha}$ regular curves in Carnot groups, J. Anal. Math., 146 (2022), 299-326.
doi: 10.1007/s11854-021-0194-z.
|
| [3] |
G. B. Folland and E. M. Stein, Hardy Spaces on Homogeneous Groups, vol. 28 of Mathematical Notes, Princeton University Press, Princeton, NJ; University of Tokyo Press, Tokyo, 1982.
|
| [4] |
Y. Guivarc'h, Croissance polynomiale et périodes des fonctions harmoniques, Bull. Soc. Math. France, 101 (1973), 333-379. http://www.numdam.org/item?id = BSMF_1973__101__333_0.
doi: 10.24033/bsmf.1764.
|
| [5] |
V. Magnani, The coarea formula for real-valued Lipschitz maps on stratified groups, Math. Nachr., 278 (2005), 1689-1705.
doi: 10.1002/mana.200310334.
|
| [6] |
V. Magnani, Towards differential calculus in stratified groups, J. Aust. Math. Soc., 95 (2013), 76-128.
doi: 10.1017/S1446788713000098.
|
| [7] |
P. Pansu, Métriques de Carnot-Carathéodory et quasiisométries des espaces symétriques de rang un, Ann. of Math. (2), 129 (1989), 1-60.
doi: 10.2307/1971484.
|
| [8] |
G. Speight and S. Zimmerman, A $C^{m, \omega}$ Whitney extension theorem for horizontal curves in the Heisenberg group, J. Geom. Anal., 33 (2023), Paper No. 182, 24.
doi: 10.1007/s12220-023-01233-w.
|
| [9] |
B. Warhurst, Contact and Pansu differentiable maps on Carnot groups, Bull. Aust. Math. Soc., 77 (2008), 495-507.
doi: 10.1017/S0004972708000440.
|
| [10] |
S. Zimmerman, Singular integrals on $C_{w^*}^{1, \alpha}$ regular curves in Banach duals, Ann. Funct. Anal., 13 (2022), Paper No. 32, 24.
doi: 10.1007/s43034-022-00178-5.
|