reserve i,j,k for Nat;

theorem Th15:
  for K being left_zeroed right_zeroed add-associative
right_complementable non empty addLoopStr holds the_inverseOp_wrt the addF of
  K = comp K
proof
  let K be left_zeroed right_zeroed add-associative right_complementable non
  empty addLoopStr;
A1: comp K is_an_inverseOp_wrt the addF of K by Th13;
  the addF of K is having_a_unity & the addF of K is having_an_inverseOp
  by Th8,Th14;
  hence thesis by A1,FINSEQOP:def 3;
end;
