theorem Th27:
  mlt(i|->c,R) = c*R
proof
A1: R is i-element FinSequence of COMPLEX by FINSEQ_1:102;
  reconsider s=c as Element of COMPLEX by XCMPLX_0:def 2;
  mlt(i|->s,R) = multcomplex[;](s,R) by A1,FINSEQOP:20
    .= c*R by A1,FINSEQOP:22;
  hence thesis;
end;
