Rigidity of singular de-Sitter tori with respect to their lightlike bi-foliation
Martin Mion-Mouton
TL;DR
The work introduces and analyzes singular Lorentzian surfaces of constant curvature, focusing on de-Sitter tori with a single conical singularity. It develops a robust framework linking geometry to 1D dynamics via lightlike foliations, HIET-based polygon constructions, and a surgery toolkit to navigate the deformation space. A principal achievement is a rigidity result: de-Sitter tori with one singularity are determined by the topological class of their lightlike foliations, with deformation data captured by projective asymptotic cycles. The paper also builds a structured deformation space, proves its Hausdorff property, and provides existence results for families realizing prescribed asymptotic-cycle data, paving the way for a Lorentzian analogue of uniformization in this singular setting.
Abstract
In this paper, we introduce a natural notion of constant curvature Lorentzian surfaces with conical singularities, and provide a large class of examples of such structures. We moreover initiate the study of their global rigidity, by proving that de-Sitter tori with a single singularity of a fixed angle are determined by the topological equivalence class of their lightlike bi-foliation. While this is reminiscent of Troyanov's uniformization results on Riemannian surfaces with conical singularities, the rigidity will come from topological dynamics in the Lorentzian case.
