theorem Th46:
  (a (#) Rseq) * seq = a * (Rseq * seq)
proof
  let n be Element of NAT;
  thus ((a (#) Rseq) * seq).n = (a (#) Rseq).n * seq.n by Def7
    .= (a * Rseq.n) * seq.n by SEQ_1:9
    .= a * (Rseq.n * seq.n) by RLVECT_1:def 7
    .= a * (Rseq * seq).n by Def7
    .= (a * (Rseq * seq)).n by NORMSP_1:def 5;
end;
