On type-I singularities in Ricci flow

  title={On type-I singularities in Ricci flow},
  author={Joerg Enders and Reto Muller and Peter M. Topping},
  journal={Communications in Analysis and Geometry},
We dene several notions of singular set for Type I Ricci ows and show that they all coincide. In order to do this, we prove that blow-ups around singular points converge to nontrivial gradient shrinking solitons, thus extending work of Naber [15]. As a byproduct we conclude that the volume of a nite-volume singular set vanishes at the singular time. We also dene a notion of density for Type I Ricci ows and use it to prove a regularity theorem reminiscent of White’s partial regularity result for… 

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