conom ie ▁politique ▁pure ▁( Elements ▁of ▁P ure ▁Econom ics ). ▁ ▁Wal ras ' ▁law ▁was ▁introduced ▁as ▁a ▁theoretical ▁answer ▁to ▁the ▁problem ▁of ▁determ ining ▁the ▁solutions ▁in ▁general ▁equilibrium . ▁ ▁His ▁notation ▁is ▁different ▁from ▁modern ▁notation ▁but ▁can ▁be ▁constructed ▁using ▁more ▁modern ▁summ ation ▁notation . ▁ ▁Wal ras ▁assumed ▁that ▁in ▁equilibrium , ▁all ▁money ▁would ▁be ▁spent ▁on ▁all ▁goods : ▁every ▁good ▁would ▁be ▁sold ▁at ▁the ▁market ▁price ▁for ▁that ▁good ▁and ▁every ▁bu yer ▁would ▁exp end ▁their ▁last ▁doll ar ▁on ▁a ▁basket ▁of ▁goods . ▁ ▁Starting ▁from ▁this ▁assumption , ▁Wal ras ▁could ▁then ▁show ▁that ▁if ▁there ▁were ▁n ▁mark ets ▁and ▁n - 1 ▁mark ets ▁cleared ▁( re ached ▁equilibrium ▁conditions ) ▁that ▁the ▁n th ▁market ▁would ▁clear ▁as ▁well . ▁ ▁This ▁is ▁easiest ▁to ▁visual ize ▁with ▁two ▁mark ets ▁( cons ider ed ▁in ▁most ▁texts ▁as ▁a ▁market ▁for ▁goods ▁and ▁a ▁market ▁for ▁money ). ▁ ▁If ▁one ▁of ▁two ▁mark ets ▁has ▁reached ▁an ▁equilibrium ▁state , ▁no ▁additional ▁goods ▁( or ▁convers ely , ▁money ) ▁can ▁enter ▁or ▁exit ▁the ▁second ▁market , ▁so ▁it ▁must ▁be ▁in ▁a ▁state ▁of ▁equilibrium ▁as ▁well . ▁ ▁Wal ras ▁used ▁this ▁statement ▁to ▁move ▁toward ▁a ▁proof ▁of ▁existence ▁of ▁solutions ▁to ▁general ▁equilibrium ▁but ▁it ▁is ▁commonly ▁used ▁today ▁to ▁illustrate ▁market ▁clear ing ▁in ▁money ▁mark ets ▁at ▁the ▁under grad uate ▁level .