Quasiconvexity at the boundary and weak lower semicontinuity of integral functionals

It is well-known that Morrey's quasiconvexity is closely related to gradient Young measures,

i.e., Young measures generated by sequences of gradients in

$L^p(\Omega;\mathbb{R}^{m\times n})$. Concentration effects,

however, cannot be treated by Young measures. One way how to describe both oscillation and

concentration effects in a fair generality are the so-called DiPerna-Majda measures.

DiPerna and Majda showed that having a sequence $\{y_k\}$ bounded in $L^p(\Omega;\mathbb{R}^{m\times n})$,$1\le p$ $0$.