$\forall$${\it ds}$,${\it da}$,$x$,$T$:top, ${\it ks}$:(top List), ${\it tr}$:top, $j$,$i$:Id.
\\[0ex]sqequal(R{-}has{-}loc(R{-}state{-}var($i$; ${\it ds}$; ${\it da}$; $x$; $T$; ${\it ks}$; ${\it tr}$); $j$); eq\_id($i$; $j$))