theorem
  for G being strict finite Group st card G = p holds
  G is p-commutative-group
proof
  let G be strict finite Group;
  assume
A1: card G = p;
  p = p |^1; then
A2: G is p-group by A1;
  G is cyclic Group by A1,GR_CY_1:21;
  hence thesis by A2;
end;
