Proposition 3.1 The plan c is a solution to the social planner's problem if and only if U(c,2)1Uc(C,2,)=F(k,) (3.1) U.(c,)=1-6+Fx(k+1,l) (3.2) BUc(C+1,+1) k1=F(k,l,)+(1-δ)k-C, (3.3) ko>0 given,and lim B'U(C,)k=0 (3.4) t>00 电子科大经管学院马捷 11Proposition 3.1  The plan is a solution to the social planner’s problem if and only if 电子科大经管学院 马捷 11     0 , , t t t t c l k 0 , lim ( , ) 0 ( 3.4 ) ( , ) ( 1 ) ( 3.3 ) 1 ( , ) ( 3.2 ) ( , ) ( , ) ( , ) / ( , ) ( , ) ( 3.1 ) 0 1 1 1 1 1 1                   c t t t t t t t t t t K t t c t t c t t z t t c t t L t t k given and U c z k k F k l k c F k l U c z U c z U c z U c z F k l    