reserve x,y for set,
  n,m for Nat,
  r,s for Real;

theorem Th8:
  for f be FinSequence, n be Nat holds (f|n)^(f/^n) = f
proof
  let f be FinSequence, n be Nat;
  reconsider D = rng f \/ {1} as non empty set;
  f is FinSequence of D by FINSEQ_1:def 4,XBOOLE_1:7;
  hence thesis by Th8A;
end;
