deffunc H₂( Nat) -> Element of CNS = z * (S . $1);
consider S being sequence of CNS such that
A1: for n being Element of NAT holds S . n = H₂(n) from FUNCT_2:sch 4();
take S ; :: thesis: for n being Nat holds S . n = z * (S . n)
let n be Nat; :: thesis: S . n = z * (S . n)
n in NAT by ORDINAL1:def 12;
hence S . n = z * (S . n) by A1; :: thesis: verum