theorem
  Product <%c1,c2%> = c1 * c2
proof
  c1 in COMPLEX & c2 in COMPLEX by XCMPLX_0:def 2;
  then multcomplex "**" <%c1,c2%> = multcomplex.(c1,c2) by AFINSQ_2:38
     .= c1*c2 by BINOP_2:def 5;
  hence thesis;
end;
