theorem Th8:
  for V be Abelian add-associative right_zeroed non empty
  addLoopStr holds Sum({}V) = 0.V
proof
  let V be Abelian add-associative right_zeroed non empty addLoopStr;
  Sum(<*>(the carrier of V)) = 0.V by RLVECT_1:43;
  hence thesis by Def2,RELAT_1:38;
end;
