let s, n be Nat; :: thesis: for f being s + 1 -element complex-valued FinSequence st f is a_solution_of_Sierp168 holds
n (#) f is a_solution_of_Sierp168

let f be s + 1 -element complex-valued FinSequence; :: thesis: ( f is a_solution_of_Sierp168 implies n (#) f is a_solution_of_Sierp168 )
assume A1: Sum (((f | s) ") ^2) = 1 / ((f . (s + 1)) ^2) ; :: according to NUMBER15:def 12 :: thesis: n (#) f is a_solution_of_Sierp168
set g = n (#) f;
A2: (n (#) f) . (s + 1) = n * (f . (s + 1)) by VALUED_1:6;
A3: (n (#) (f | s)) ^2 = (n ^2) (#) ((f | s) ^2) by BORSUK_7:18;
A4: ((f | s) ") ^2 = ((f | s) ^2) " by Th57;
A5: ((n (#) (f | s)) ") ^2 = ((n (#) (f | s)) ^2) " by Th57;
A6: ((n ^2) (#) ((f | s) ^2)) " = (1 / (n ^2)) (#) (((f | s) ^2) ") by Th58;
(n (#) f) | s = n (#) (f | s) by Th56;
hence Sum ((((n (#) f) | s) ") ^2) = (1 / (n ^2)) * (Sum (((f | s) ^2) ")) by A3, A5, A6, RVSUM_2:38
.= (1 * 1) / ((n ^2) * ((f . (s + 1)) ^2)) by A1, A4, XCMPLX_1:76
.= 1 / (((n (#) f) . (s + 1)) ^2) by A2 ;
:: according to NUMBER15:def 12 :: thesis: verum