On essential self-adjointness for first order differential operators on domains in $\mathbb R^d$
On essential self-adjointness for first order differential operators on domains in $\mathbb R^d$
We consider general symmetric systems of first order linear partial differential operators on domains \Omega \subset \mathbb R^d , and we seek sufficient conditions on the coefficients which ensure essential self-adjointness. The coefficients of the first order terms are only required to belong to C^1 (\Omega) and there is no …