Date/heure
20 octobre 2025
15:30 - 16:30
Oratrice ou orateur
Mario Gauvrit
Catégorie d'évènement Séminaire de géométrie différentielle
Résumé
We investigate the stability of the Morse index for a sequence of Yang–Mills connections on closed 4-manifolds under bubble-tree convergence. As critical points of a conformally invariant energy, Yang–Mills connections share close ties with harmonic maps in various respects. At the same time, their analysis is simpler provided one works in a suitable gauge, namely the Coulomb gauge. Motivated by applications to the construction of non-stable solutions of the Yang–Mills equations, this work extends recent methods developed by Da Lio–Gianocca–Rivière for index stability to the Yang–Mills framework, employing sharp decay estimates to show that the neck regions contribute positively to the second variation.