Care tutte, cari tutti, Con la presente si annuncia il seguente seminario di Analisi: Giovedì 17 settembre 2026, alle 16:00, in Aula Seminari, avremo il piacere di ascoltare Lars Eric Hientzsch (Karlsruher Institut für Technologie), che terrà un seminario<https://www.dm.unipi.it/seminario/?id=6a96bc0ed609e127602c55c6> dal titolo “On leapfrogging vortex rings for the Euler equations”. Trovate l'abstract qui sotto. A presto, Luigi. ————————————————— Dear all, We announce the following Analysis seminar: on Thursday, 17 sept. 2026, 4pm, in Aula Seminari, we will have the pleasure of listening to Lars Eric Hientzsch (Karlsruher Institut für Technologie). The title of the talk<https://www.dm.unipi.it/seminario/?id=6a96bc0ed609e127602c55c6> is “On leapfrogging vortex rings for the Euler equations”. Please find the abstract below. Best regards, Luigi ----------------------------------- Speaker: Lars Eric Hientzsch (Karlsruher Institut für Technologie) Title: On leapfrogging vortex rings for the Euler equations Abstract: In 1858, Helmholtz conjectured that coaxial vortex rings in 3D inviscid fluids can exhibit the "leapfrogging" dynamics, where rings repeatedly pass through one another. While well-documented experimentally, this phenomenon involves singular interactions that are difficult to capture analytically. In this talk, we present a rigorous justification of these dynamics for the 3D incompressible Euler equations. We consider a general class of initial data corresponding to N sharply concentrated coaxial vortex rings and prove that the leapfrogging motion persists on a logarithmic time scale. The core of the analysis requires new estimates to propagate the concentration of vorticity despite the singular mutual interactions required for the phenomenon to occur. Joint work with M. Donati, C. Lacave, and E. Miot. ----------- Luigi Forcella, Associate Professor University of Pisa Department of Mathematics Largo Bruno Pontecorvo 5 57127 Pisa, Italy https://pagine.dm.unipi.it/forcella/index.html