On type-II singularities in Ricci flow on
arXiv:1210.4089
Abstract
In each dimension and for each real number , we construct a family of complete rotationally symmetric solutions to Ricci flow on which encounter a global singularity at a finite time . The singularity forms arbitrarily slowly with the curvature blowing up arbitrarily fast at the rate . Near the origin, blow-ups of such a solution converge uniformly to the Bryant soliton. Near spatial infinity, blow-ups of such a solution converge uniformly to the shrinking cylinder soliton. As an application of this result, we prove that there exist standard solutions of Ricci flow on whose blow-ups near the origin converge uniformly to the Bryant soliton.
Revised version, typos corrected