Optimal Gevrey Regularity for Certain Sums of Squares in Two Variables

Antonio Bove, Marco Mughetti

For $q$, $a$ integers such that $a\ge 1$, $1<q$, $(x,y)\in U$, $U$ a neighborhood of the origin in ${\mathbb{R}}^2$, we consider the operator $$ D_{x}^{2} + x^{…