Exhibit a polynomial$-$time reduction from the language P representing the PARTITION PROBLEM as defined in Exercise $6\mathrm{.}5$ to the language SS representing the SUBSET$-$SUM PROBLEM defined in section $6\mathrm{.}2($the PARTITION PROBLEM is known to be NP$-$complete. The reduction will show that the SUBSET$-$SUM PROBLEM is also NP$-$complete.$)$