reserve f for Function;
reserve n,k,n1 for Nat;
reserve r,p for Real;
reserve x,y,z for object;
reserve seq,seq1,seq2,seq3,seq9,seq19 for Real_Sequence;

theorem
  seq2(#)(seq1/"seq)=(seq2(#)seq1)/"seq
proof
  thus seq2(#)(seq1/"seq) = seq2(#)(seq1(#)(seq"))
    .=(seq2(#)seq1)/"seq by Th14;
end;
