The chains of left-invariant CR structures on the 3-dimensional Lie groups
Let G be a 3-dimensional connected Lie group with a left-invariant nondegenerate CR structure. We show that all the chains on G are closed if and only if G is CR equivalent to one of the left-invariant spherical CR structures on SU(2), SO(3) and a quotient group of the Heisenberg group.
math.CV↗