Definition checkPrfFA1 (p recs : nat) :=
  let A := cPairPi1 (cPairPi2 (cPairPi2 p)) in
  let v := cPairPi1 (cPairPi2 (cPairPi2 (cPairPi2 p))) in
  let t := cPairPi2 (cPairPi2 (cPairPi2 (cPairPi2 p))) in
  wellFormedTerm t *
  charFunction 2 beq_nat
    (cPair 1 (cPair (cPair 3 (cPair v A)) (codeSubFormula A v t)))
    (cPairPi1 p).

(* Specifications: *)
Lemma checkPrfFA1IsPR : isPR 2 checkPrfFA1.