Let $g$ be a map defined as the Nisan-Wigderson generator
but based on an $NP \cap coNP$-function $f$. Any string $b$ outside the range of
$g$ determines a propositional tautology $\tau(g)_b$ expressing this
fact. Razborov \cite{Raz03} has conjectured that if $f$ is hard on average for
P/poly then these ... more >>>