2026/07/19 by Raphaël Danchin, In-Jee Jeong
#math.AP
We consider the initial value problem for the vorticity equation in the endpoint critical Sobolev space Wd,1(ℝd) for d = 2, 3. In two dimensions, we prove global propagation of the W2,1(ℝ2) regularity of the vorticity. In three dimensions, for axisymmetric flows without swirl, we propagate W3,1(ℝ3) regularity of the vorticity for all times. These are in stark contrast to existing strong ill-posedness results in critical Sobolev spaces Wd/p,p(ℝd) for all 1 < p < ∞, which were based on axisymmetric flows without swirl when d = 3.