

Ricci curvature, fundamental group and the Milnor conjecture (I)
By Aaron Naber


Ricci curvature, fundamental group and the Milnor conjecture (II)
By Daniele Semola


On Gromov’s rigidity theorem for polytopes with acute angles
By Yipeng Wang
By Robert Young
Appears in collection : Not Only Scalar Curvature Seminar
In 1979, Kaufman constructed a remarkable surjective Lipschitz map from a cube to a square whose derivative has rank 1 almost everywhere. In this talk, we will present some higher-dimensional generalizations of Kaufman's construction that lead to Lipschitz and Hölder maps with wild properties, including: topologically nontrivial maps from $S^m$ to $S^n$ with derivative of rank $n-1$, $\frac{2}{3}-\epsilon$--Hölder approximations of surfaces in the Heisenberg group, and Hölder maps from the disc to the disc that preserve signed area but approximate an arbitrary continuous map.