equation icon  ( ^z ) -s-ie+ sum oo oo sum Rn0 = eieke-i^z(ek)-n-ie+ ^zn+ie+ ---- 1 Cn,j^zn- j ek n=- oo j=0 ( ) -s-ie+ sum oo oo sum = eieke-i^z(ek)-n-ie+ ^zn+ie+ ^z--- 1 C z^k, (161) ek n,n- k k=- oo n=k ( )- s- ie oo oo n -i^z n -s-ie+ n+ie+ -^z- + sum sum n+j R C = e 2 (ek) z^ ek - 1 Dn,j^z n=- oo j=0 ( )- s- ie+ sum oo sum k = e-i^z2n(ek)-s-ie+z^n+ie+ -^z-- 1 Dn,k-n^zk, (162) ek k=- oo n=- oo