A note on blowup limits in 3d Ricci flow

Abstract

We prove that Perelman's ancient ovals occur as blowup limit in 3d Ricci flow through singularities if and only if there is an accumulation of spherical singularities.

An optimal volume growth estimate for noncollapsed steady gradient Ricci solitons

“…[GZ08]) is modeled on a Bryant soliton. We remark that by the recent work of Choi-Haslhofer [CH21], if we consider the more general singular Ricci flow (c.f. [KL17, BK17]) instead of Ricci flow, then there could possibly be non-solitonic blow-up limits.…”