J. Orobitg | Searcharxiv

arXiv2021

The regularity of the boundary of vortex patches for some non-linear transport equations

We prove the persistence of boundary smoothness of vortex patches for a non-linear transport equation in $\mathbb{R}^n$ with velocity field given by convolution of the density with an odd kernel, homogeneous of degree $-(n-1)$ and of class $C^2(\mathbb{R}^n\setminus\{0\}, \mathbb{R}^n).$ This allows the velocity field to have non-trivial divergence. The quasi-geostrophic equation in $\mathbb{R}^3$ and the Cauchy transport equation in the plane are examples.

math.AP↗

arXiv2017

Distributional solutions of the Beltrami equation

We study the distributional solutions to the (generalized) Beltrami equation under Sobolev assumptions on the Beltrami coefficients. In this setting, we prove that these distributional solutions are true quasiregular maps and they are smoother than expected, that is, they have second order derivatives in $L^{1+\varepsilon}_{loc}$, for some $\varepsilon >0$.

math.AP↗