theorem Th21:
  for k being Nat holds
  for p being finite NAT-defined (the InstructionsF of S)-valued Function
   holds dom Reloc(p,k) = { j+k where j is Nat:j in dom p }
proof
  let k be Nat;
  let p be finite NAT-defined (the InstructionsF of S)-valued Function;
  thus dom Reloc(p,k) = dom Shift(p,k) by Th20
    .= { j+k where j is Nat:j in dom p } by VALUED_1:def 12;
end;
