theorem Th62:
  for V being non empty CLSStruct, M being empty Subset of V, z
  being Complex holds z * M = {}
proof
  let V be non empty CLSStruct;
  let M be empty Subset of V;
  let z be Complex;
  now
    let x be VECTOR of V;
    assume x in z * M;
    then ex v be VECTOR of V st x = z * v & v in {};
    hence x in {};
  end;
  then z * M c= {};
  hence thesis;
end;
