reserve x for Real;

theorem
  for n be non zero Nat for x be Element of COMPLEX for v be CRoot of n
  ,x st v = 0 holds x = 0
proof
  let n be non zero Nat;
  let x be Element of COMPLEX;
  let v be CRoot of n,x;
  assume v = 0;
  then n >= 0+1 & 0|^n = x by Def2,NAT_1:13;
  hence thesis by NEWTON:11;
end;
