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A Nash-Kuiper theorem for isometric immersions beyond Borisov's exponent

by Prof. Jonas Hirsch

This is my image.
This is my image.
This is my image.

16:00-17:00 Tuesday, 1 April 2025
Auditorium, Rectorate



Abstract

For any given short embedding from an n-dimensional region into (n1)-dimensional Euclidean space, and for any Hölder exponent α<(n2n+1)1, a C1,α isometric embedding is built within any C0 neighbourhood of the given short embedding through convex integration, which refines the classical Nash-Kuiper theorem and extends the flexibility of C1,α isometric embedding beyond Borisov’s exponent. Notably, when n=2, we attain the Onsager exponent 1/3 for isometric embeddings. This convex integration scheme is performed through new construction and leveraging iterative “integration by parts” to effectively transfer large-scale errors to smaller ones. In my talk, I would like to give some ideas for the “integration by parts” procedure. Furthermore, I will highlight the differences between the schemes that were previously used. This is a joint work with Wentao Cao, and Dominik Inauen.