Pa(g>是cs(1-s-ip4, i=0 P(t)= s-2t,0etg Fp(s)c(1-si 1=0 s-2t-1 stal             = −    = −  − =  − =    =  − =  − = t 1 2 1 s 2 t 1 , , n i 0 n i n P n i ( 1 s ) i s i n (s) C b P 2 1 s 2t,0 t , n i 0 i i P n i ( 1 s ) i s i n (s) C a P P(t)