For a permutation group $G$ acting on the set $\Omega$
we say that two strings $x,y\,:\,\Omega\to\boole$
are {\em $G$-isomorphic} if they are equivalent under
the action of $G$, \ie, if for some $\pi\in G$ we have
$x(i^{\pi})=y(i)$ for all $i\in\Omega$.
Cyclic Shift, Graph Isomorphism ... more >>>