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
  for f being non-zero PartFunc of NAT,REAL holds rng f c= REAL \ {0}
    by ORDINAL1:def 15,ZFMISC_1:34;
