▁and ▁topological ▁fixed - point ▁theory ▁to ▁economic ▁analysis . ▁Their ▁work ▁thereby ▁avoided ▁the ▁traditional ▁differential ▁calculus , ▁for ▁which ▁the ▁maximum – operator ▁did ▁not ▁apply ▁to ▁non - d iffer enti able ▁functions . ▁Cont inu ing ▁von ▁Ne umann ' s ▁work ▁in ▁co oper ative ▁game ▁theory , ▁game ▁the or ists ▁Lloyd ▁S . ▁Sh ap ley , ▁Martin ▁Sh ub ik , ▁Her vé ▁Mou lin , ▁N im rod ▁Meg id do , ▁Bez ale l ▁Pe leg ▁influenced ▁economic ▁research ▁in ▁politics ▁and ▁econom ics . ▁For ▁example , ▁research ▁on ▁the ▁fair ▁prices ▁in ▁co oper ative ▁games ▁and ▁fair ▁values ▁for ▁voting ▁games ▁led ▁to ▁changed ▁rules ▁for ▁voting ▁in ▁legisl atures ▁and ▁for ▁account ing ▁for ▁the ▁costs ▁in ▁public – works ▁projects . ▁For ▁example , ▁co oper ative ▁game ▁theory ▁was ▁used ▁in ▁design ing ▁the ▁water ▁distribution ▁system ▁of ▁Southern ▁Sweden ▁and ▁for ▁setting ▁rates ▁for ▁dedicated ▁tele phone ▁lines ▁in ▁the ▁USA . ▁ ▁Ear lier ▁ne oc lass ical ▁theory ▁had ▁bounded ▁only ▁the ▁range ▁of ▁b arg aining ▁out comes ▁and ▁in ▁special ▁cases , ▁for ▁ ▁example ▁bil ater al ▁mon opol y ▁or ▁along ▁the ▁contract ▁curve ▁of ▁the ▁Ed gew orth ▁box . ▁ ▁Von ▁Ne umann ▁and ▁M orgen st ern ' s ▁results ▁were ▁similarly ▁weak . ▁Following ▁von ▁Ne umann ' s ▁program , ▁however , ▁John ▁Nash ▁used ▁fixed – point ▁theory ▁to ▁prove ▁conditions ▁under ▁which ▁the