Best linear unbiased estimators of the fixed and random effects of mixed linear models are available when the true values of the variance ratios are known. If the true values are replaced by estimated ...

It is shown that the Ritz projection onto spaces of piecewise linear finite elements is bounded in the Sobolev space, $\overset {\circ} {W}_p^1$, for $2 \leqslant p \leqslant \infty$.