Our main aim is to present a geometrically meaningful formula for the fundamental
solutions to a second order sub-elliptic differential equation and to the heat equation associated with
a sub-elliptic operator in the sub-Riemannian geometry on the unit sphere $S^3$. Our method is based
on the Hamiltonian-Jacobi approach, where the corresponding Hamitonian system is solved with
mixed boundary conditions. A closed form of the modified action is given. It is a sub-Riemannian
invariant and plays the role of a distance on $S^3$.
@article{1298989627,
author = {Chang, Der-Chen and Markina, Irina and Vasil'ev, Alexander},
title = {Modified Action and Differential Operators on the 3-D Sub-Riemannian Sphere},
journal = {Asian J. Math.},
volume = {14},
number = {1},
year = {2010},
pages = { 439-474},
language = {en},
url = {http://dml.mathdoc.fr/item/1298989627}
}
Chang, Der-Chen; Markina, Irina; Vasil'ev, Alexander. Modified Action and Differential Operators on the 3-D Sub-Riemannian Sphere. Asian J. Math., Tome 14 (2010) no. 1, pp. 439-474. http://gdmltest.u-ga.fr/item/1298989627/