English

CD meets CAT

Differential Geometry 2018-01-23 v3 Metric Geometry

Abstract

We show that if a noncollapsed CD(K,n)CD(K,n) space XX with n2n\ge 2 has curvature bounded above by κ\kappa in the sense of Alexandrov then K(n1)κK\le (n-1)\kappa and XX is an Alexandrov space of curvature bounded below by Kκ(n2)K-\kappa (n-2). We also show that if a CD(K,n)CD(K,n) space YY with finite nn has curvature bounded above then it is infinitesimally Hilbertian.

Keywords

Cite

@article{arxiv.1712.02839,
  title  = {CD meets CAT},
  author = {Vitali Kapovitch and Christian Ketterer},
  journal= {arXiv preprint arXiv:1712.02839},
  year   = {2018}
}

Comments

We add a new section where we prove a new theorem that if a $CD(K,n)$ space with finite $n$ has curvature bounded above then it is infinitesimally Hilbertian. Using this we remove the infinitesimal Hilbertianness assumption from the main theorem. Minor corrections, additional references

R2 v1 2026-06-22T23:11:42.940Z