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
  (-seq1)(#)seq2=-(seq1(#)seq2) & seq1(#)(-seq2)=-(seq1(#)seq2) by Th18;
