reserve T for non empty Abelian
  add-associative right_zeroed right_complementable RLSStruct,
  X,Y,Z,B,C,B1,B2 for Subset of T,
  x,y,p for Point of T;

theorem
  (X (O) B) (-) B c= X (-) B & (X (O) B) (+) B c= X (+) B
proof
  X (O) B c= X by Th41;
  hence thesis by Th9;
end;
