reserve n for Nat;

theorem
for R being unital non degenerated doubleLoopStr holds LC npoly(R,n) = 1.R
proof
let R be unital non degenerated doubleLoopStr;
set q = npoly(R,n);
A: n = deg q by lem6 .= len q - 1 by HURWITZ:def 2;
then n + 1 = len q;
then len q -' 1 = n by A,XREAL_1:233,NAT_1:11;
hence thesis by Lm10;
end;
