On the Sobolev quotient of three-dimensional CR manifolds
Jih-Hsin Cheng
Academia Sinica and NCTS 6F, Taipei, Taiwan (R.O.C.)Andrea Malchiodi
Scuola Normale Superiore, Pisa, ItalyPaul Yang
Princeton University, USA
Abstract
We exhibit examples of compact three-dimensional CR manifolds of positive Webster class, Rossi spheres, for which the pseudo-hermitian mass, as defined by Cheng–Malchiodi–Yang (2017), is negative, and for which the infimum of the CR-Sobolev quotient is not attained. To our knowledge, this is the first geometric context on smooth closed manifolds where this phenomenon arises, in striking contrast to the Riemannian case.
Cite this article
Jih-Hsin Cheng, Andrea Malchiodi, Paul Yang, On the Sobolev quotient of three-dimensional CR manifolds. Rev. Mat. Iberoam. 39 (2023), no. 6, pp. 2017–2066
DOI 10.4171/RMI/1412