# Seminars & Colloquia Calendar

Geometric Analysis Seminar

## Compactness and partial regularity theory of Ricci flows in higher dimensions

#### Richard Bamler (UC Berkeley)

Location:  zoom
Date & time: Tuesday, 08 December 2020 at 2:50PM - 3:50PM

We present a new compactness theory of Ricci flows. This theory states that any sequence of Ricci flows that is pointed in an appropriate sense, subsequentially converges to a synthetic flow. Under a natural non-collapsing condition, this limiting flow is smooth on the complement of a singular set of parabolic codimension at least 4. We furthermore obtain a stratification of the singular set with optimal dimensional bounds depending on the symmetries of the tangent flows. Our methods also imply the corresponding quantitative stratification result and  the expected $$L^p$$-curvature bounds.

As an application we obtain a description of the singularity formation at the first singular time and a long-time characterization of immortal flows, which generalizes the thick-thin decomposition in dimension 3. We also obtain a backwards pseudolocality theorem and discuss several other applications.

Please email DanielKetover at
dk927@rutgers.edu to either be added to the list of invitees or to attend a particular talk.

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