theorem
  c*<*c1*> = <*c*c1*>
proof
  reconsider s=c, s1=c1 as Element of COMPLEX by XCMPLX_0:def 2;
  s*<*s1*> = <*(multcomplex[;](s,id COMPLEX)).s1*> by FINSEQ_2:35
          .= <*c*c1*> by Lm1;
  hence thesis;
end;
