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 Th40:
  seq is non-zero implies (-seq)"=(-1r)(#)seq"
proof
  (-1)" = -1;
  hence thesis by Th39;
end;
