reserve f for Function;
reserve n,k,n1 for Element of NAT;
reserve r,p for Complex;
reserve x,y for set;
reserve seq,seq1,seq2,seq3,seq9,seq19 for Complex_Sequence;

theorem
  seq2 (#) (seq1 /" seq) = (seq2 (#) seq1) /" seq
proof
  thus seq2 (#) (seq1 /" seq) = seq2 (#) seq1 (#) (seq") by Th8
    .= (seq2 (#) seq1) /" seq;
end;
