Approximation in higher-order Sobolev spaces and Hodge systems

Pierre Bousquet, Emmanuel Russ, Yi Wang +1

Let $d\ge 2$ be an integer, $1\le l\le d-1$ and $\phi$ be a differential $l$-form on ${\mathbb{R}}^d$ with ${\dot{W}}^{1,d}$ coefficients. It was proved by Bourgain and Brezis (\cite[…