reserve x for set;
reserve a, b, c, d, e for Real;
reserve m, n, m1, m2 for Nat;
reserve k, l for Integer;
reserve p for Rational;

theorem Th5:
  for n being Nat st n>=1 holds n-root 0 = 0
proof
  let n be Nat;
  assume
A1: n>=1;
  hence n-root 0 = n -Root 0 by Def1
    .= 0 by A1,PREPOWER:def 2;
end;
