English

Secondary Characteristic Classes in CR Geometry

Differential Geometry 2026-08-03 v1 Complex Variables

Abstract

We construct a family of R/Z\mathbb{R}/\mathbb{Z}-valued CR invariants for compact strictly pseudoconvex CR manifolds admitting pseudo-Einstein contact forms. We define these invariants by applying the theory of Cheeger--Simons differential characters to a globally defined modification of the normal tractor connection. When the CR holomorphic tangent bundle is trivial, their natural R\mathbb{R}-valued lifts agree with the generalized Burns--Epstein invariants. For CR manifolds arising as boundaries of relatively compact strictly pseudoconvex domains, we identify these differential characters with those determined by the renormalized connection and derive bulk--boundary formulas involving renormalized characteristic numbers and residues of Chern classes. These formulas recover and extend the results of Burns--Epstein and Marugame. We also obtain obstructions to CR embeddings into complex Euclidean space.

Cite

@article{arxiv.2608.01859,
  title  = {Secondary Characteristic Classes in CR Geometry},
  author = {Shuya Matsumoto},
  journal= {arXiv preprint arXiv:2608.01859},
  year   = {2026}
}

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40 pages