Fisher intertemporal choice intertemporal choice 12 765rU 9 C2=Y2+(1+r)S1 2=Y2+(1+r)(X1-C1) (1+r)C1+C2=(1+r)X1+Y2 1+rFisher & intertemporal choice intertemporal choice 1 Y1 C1 S = − 2 2 1 C =Y +(1+ r)S (1 )( ) 2 2 Y1 C1 C =Y + + r − 1 2 1 2 (1+r)C +C = (1+r)Y +Y r Y Y r C C + = + + + 1 1 2 1 2 1