M. Mughetti

Regularity for a sum of two squares in two variables with symplectic characteristic manifold

We study the Gevrey hypoellipticity of the sum of two squares in two variables, satisfying the Hörmander hypothesis: Dx2+f(x,y)Dy2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\...