English

Semi-local simple connectedness of non-collapsing Ricci limit spaces

Differential Geometry 2025-07-08 v2 Metric Geometry

Abstract

Let XX be a non-collapsing Ricci limit space and let xXx\in X. We show that for any ϵ>0\epsilon>0, there is r>0r>0 such that every loop in Bt(x)B_t(x) is contractible in B(1+ϵ)t(x)B_{(1+\epsilon)t}(x), where t(0,r]t\in(0,r]. In particular, XX is semi-locally simply connected.

Keywords

Cite

@article{arxiv.1904.06877,
  title  = {Semi-local simple connectedness of non-collapsing Ricci limit spaces},
  author = {Jiayin Pan and Guofang Wei},
  journal= {arXiv preprint arXiv:1904.06877},
  year   = {2025}
}

Comments

Slightly modified the proof of Theorem 3.5 to fix a minor error on local covers. Slightly modified the proofs of Lemmas 3.2, 3.6, and 3.8 to fix a minor error on estimating $\rho(t,x)$ by a nearby point. Fixed some typos