The label-cover problem was introduced in \cite{ABSS} and shown
there to be quasi-NP-hard to approximate to within a factor of
$2^{\log^{1-\delta}n}$ for any {\em constant} $\delta>0$. This
combinatorial graph problem has been utilized \cite{ABSS,GM,ABMP}
for showing hardness-of-approximation of numerous problems. We
present a direct combinatorial reduction from low
error-probability PCP ... more >>>