Sharp constants in several inequalities on the Heisenberg group (Q447932)

The authors obtain sharp constants for inequalities on the Heisenberg group whose Euclidean version are the Hardy-Littlewood-Sobolev inequalities. After that, they obtain sharp constants for the Sobolev inequalities for the Laplacian and conformally invariant fractional Laplacians. As a limit case they also obtain sharp constants for the Onofri and log-Sobolev inequalities with different methodology from that used in the Euclidean setting.