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On the existence of fibered three-dimensional perfect fluid equilibria without continuous Euclidean symmetry

PDE and Applied Math Seminar

Speaker: Daniel Ginsberg, Brooklyn College -- CUNY
Related Webpage: https://dginsberg.github.io/
Location: Zoom
Start time: Thu, Nov 20 2025, 4:10PM

Following work of Lortz, we construct a family of smooth steady states of the ideal, incompressible Euler equation in three dimensions that possess no continuous Euclidean symmetry. As in Lortz, they do possess a planar reflection symmetry and, as such, all the orbits of the velocity are closed. Different from Lortz, our construction has a discrete m-fold symmetry and is foliated by invariant cylindrical level sets of a non-degenerate Bernoulli pressure. Such examples narrow the scope of validity of Grad's conjecture that the only solutions with a continuous symmetry can be fibered by pressure surfaces. This is joint work with Theodore Drivas and Tarek Elgindi. ​