H Chen, P Luo - Calculus of Variations and Partial Differential …, 2015 - Springer
Let Ω Ω be a bounded open domain in R^ n R n with smooth boundary and X=(X_1, X_2, ...,
X_m) X=(X 1, X 2,…, X m) be a system of real smooth vector fields defined on Ω Ω with the …