Sometimes I do differential geometry.
[bridged from https://mathstodon.xyz/@pschwahn on the fediverse by https://fed.brid.gy/ ]
Paul Schwahn
I must add that I am not completely happy with the petition itself: the text reads somewhat generic, there is no call to action to the Brazilian authorities, and I don't like change.org. But I still found it worth sharing.
"The fundamental group of a spherical space form is not audible", by Mauro Colantonio and Emilio A. Lauret.
A spherical space form is a complete Riemannian manifold of constant positive (sectional) curvature. The universal cover of a spherical space form is a round sphere (explaining the name) […]
My colleague Misha Verbitsky over at IMPA, one of the top mathematicians of Brazil, is being detained in Armenia because Russia has designated him a terrorist after his comments on the war in Ukraine […]
[Original post on mathstodon.xyz]
Because we care deeply about international mathematics and its mathematicians, we must recognize the threat to both that the upcoming ICM poses.
Please read and consider signing:
Move the 2026 ICM out of the United States […]
poor 𝑆²×ℝ 😢
Two exciting preprints on the arXiv this week, both about Einstein metrics!
P.-A. Nagy has worked out the third variation of the Ricci tensor with respect to the metric (a long-standing computational problem). This enables us to study third order deformations of Einstein metrics (for up to […]
I must admit that I never understood the theorem statement of geometrization of 3-manifolds: every (smooth, compact, connected, orientable) 3-manifold (with boundary a disjoint union of tori) "decomposes" into "geometric pieces".
But what exactly does "decompose" mean here, what are the 8 […]
Paul Schwahn
Paul Schwahn
Paul Schwahn
They made the isospectral drums
https://prismika.github.io/2026/03/01/we-made-the-isospectral-drums.html
