English

C-projective geometry

Differential Geometry 2021-06-08 v2

Abstract

We develop in detail the theory of c-projective geometry, a natural analogue of projective differential geometry adapted to complex manifolds. We realise it as a type of parabolic geometry and describe the associated Cartan or tractor connection. A Kaehler manifold gives rise to a c-projective structure and this is one of the primary motivations for its study. The existence of two or more Kaehler metrics underlying a given c-projective structure has many ramifications, which we explore in depth. As a consequence of this analysis, we prove the Yano-Obata conjecture for complete Kaehler manifolds: if such a manifold admits a one parameter group of c-projective transformations that are not affine, then it is complex projective space, equipped with a multiple of the Fubini-Study metric.

Keywords

Cite

@article{arxiv.1512.04516,
  title  = {C-projective geometry},
  author = {David M. J. Calderbank and Michael G. Eastwood and Vladimir S. Matveev and Katharina Neusser},
  journal= {arXiv preprint arXiv:1512.04516},
  year   = {2021}
}

Comments

117 pages; v2 added material on cones, local classification and outlook

R2 v1 2026-06-22T12:09:34.548Z