A metric on S² x S² with positive sectional curvature

Geometry Lunch Seminar

WhenWednesday, October 21, 2026, 12:20 pm - 1:30 pm
Where114 McAllister
SpeakerPei-Ken Hung (zoom), University of Illinois Urbana-Champaign
ContactRachel Weaver, Dmitri Burago, Anton Petrunin, Jeffrey Case, Dawit Mengesha

Abstract

We describe a construction of a positively curved metric on S2×S2. Starting from the standard metric on S2×S2, we first perform a Cheeger deformation. The resulting metric has nonnegative sectional curvature. We refer to it as a Cheeger-Mueter metric. We then consider a suitable third order perturbation of this Cheeger-Mueter metric and show that the perturbed metrics have positive sectional curvature. This is joint work with Simon Brendle.

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