$S2=\left[\begin{array}{cccc}1& 0& 1& 1\\ 0& 1& 1& 1\\ 0& 1& 0& 1\\ 1& 1& 1& 0\end{array}\right]S3=\left[\begin{array}{cccc}1& 0& 1& 0\\ 0& 1& 1& 1\\ 0& 1& 0& 0\\ 1& 1& 1& 1\end{array}\right]$For S$2,$ and S$3($since they are information sets in binary$)$ give parity$-$check equations that express each redundant bit in terms of the message bits.