▁and ▁behavior al ▁sciences ▁ ▁with ▁M SC 2 0 1 0 ▁class ifications ▁for ▁' Game ▁theory ' ▁at ▁codes ▁ 9 1 A xx ▁and ▁for ▁' Math emat ical ▁econom ics ' ▁at ▁codes ▁▁ 9 1 B xx . ▁ ▁The ▁Hand book ▁of ▁Mathemat ical ▁Econom ics ▁series ▁( Else vier ), ▁currently ▁ 4 ▁volumes , ▁distingu ishes ▁ ▁between ▁mathematical ▁methods ▁in ▁econom ics , ▁v . ▁ 1 , ▁Part ▁I , ▁and ▁areas ▁of ▁econom ics ▁in ▁other ▁volumes ▁where ▁mathematics ▁is ▁employed . ▁ ▁Another ▁source ▁with ▁a ▁similar ▁distinction ▁is ▁The ▁New ▁Pal gra ve : ▁A ▁Dictionary ▁of ▁Econom ics ▁( 1 9 8 7 , ▁ 4 ▁vol s ., ▁ 1 , 3 0 0 ▁subject ▁entries ). ▁ ▁In ▁it , ▁a ▁" Subject ▁Index " ▁includes ▁mathematical ▁entries ▁under ▁ 2 ▁head ings ▁( vol . ▁IV , ▁pp .   9 8 2 – 3 ): ▁Mathemat ical ▁Econom ics ▁( 2 4 ▁listed , ▁such ▁as ▁" acy c licity ", ▁" aggreg ation ▁problem ", ▁" com par ative ▁stat ics ", ▁" lex ic ographic ▁order ings ", ▁" linear ▁models ", ▁" order ings ", ▁and ▁" qual itative ▁econom ics ") ▁Mathemat ical ▁Method s ▁( 4 2 ▁listed , ▁such ▁as ▁" calcul us ▁of ▁variations ", ▁" cat ast rop he ▁theory ", ▁" com bin ator ics ," ▁" comput ation ▁of ▁general ▁equilibrium ", ▁" con vex