reserve A,B,p,q,r for Element of LTLB_WFF,
  M for LTLModel,
  j,k,n for Element of NAT,
  i for Nat,
  X for Subset of LTLB_WFF,
  F for finite Subset of LTLB_WFF,
  f for FinSequence of LTLB_WFF,
  g for Function of LTLB_WFF,BOOLEAN,
  x,y,z for set,
  P,Q,R for PNPair;

theorem Th2: p is FinSequence of NAT
  proof
    l c= NAT* by HILBERT1:def 5;
    then p in NAT*;
    hence thesis by FINSEQ_1:def 11;
  end;
