
## 7. Chains and pseudo-circles

1. #### Problem 7.1.

[R. Montgomery] What do pseudo-circles really mean? More precisely:

(a) Is there a variational formulation of chains and pseudo-circles? For example, is there a Finsler structure on $M^3$ which yields chains or pseudo-circles as geodesics?

(b) Is there a Fefferman-type construction that yields pseudo-circles?

Cite this as: AimPL: Analysis and geometry on pseudohermitian manifolds, available at http://aimpl.org/pshermitian.