Steiner system
= Steiner system
{c}
{title2=$S(t,k,v)$}
{wiki}
A Steiner system $S(t,k,v)$ is a $v$-point set with $k$-point blocks such that every $t$-point subset is contained in exactly one block. Necessarily the number of blocks is $\binom vt/\binom kt$. This count is a necessary consistency check, not a substitute for proving exact containment. The <small Witt design> is $S(5,6,12)$.