reserve i,j,n,n1,n2,m,k,l,u for Nat,
        r,r1,r2 for Real,
        x,y for Integer,
        a,b for non trivial Nat,
        F for XFinSequence,
        cF,cF1,cF2 for complex-valued XFinSequence,
        c,c1,c2 for Complex;

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;
