2026/05/13 by Eliseo Luongo, Umberto Pappalettera
#math.AP #math.SP
We show that the Cauchy problem associated with the parabolic-elliptic Keller-Segel model is locally ill-posed in Lq(ℝn) for dimensions n ∈ \3,…,9\ and throughout the supercritical range q∈ [1,(n)/(2)). An analog non-uniqueness result is given in the critical space of bounded functions taking values in Ln/2,∞(\Rn). The non-uniqueness is driven by an instability mechanism in self-similarity variables, in the spirit of the program proposed by Jia and Šverák for the three-dimensional Navier-Stokes equations.