theorem Th8:
  for G being unital non empty multMagma holds Product <*> the
  carrier of G = 1_G
proof
  let G be unital non empty multMagma;
  set g = the multF of G;
  len <*> the carrier of G = 0 & g is having_a_unity;
  hence Product <*> the carrier of G = the_unity_wrt g by FINSOP_1:def 1
    .= 1_G by GROUP_1:22;
end;
