reserve
  a for natural Number,
  k,l,m,n,k1,b,c,i for Nat,
  x,y,z,y1,y2 for object,
  X,Y for set,
  f,g for Function;
reserve p,q,r,s,t for FinSequence;
reserve D for set;

theorem Th24:
  for k being Nat st len p < k & k <= len(p^q) holds (p^q).k = q.(k - len p)
proof
  let k be Nat;
  assume len p < k & k <= len(p^q);
  then len p + 1 <= k & k <= len p + len q by Th22,NAT_1:13;
  hence thesis by Th23;
end;
