generalize precisionNotZero; case precision.
intros H'2; Contradict H'2; auto with zarith.
intros n; case n.
intros H'2; Contradict H'2; auto with zarith.
intros n0 H'2; replace (pred (S (S n0))) with (S n0).
apply EvenExp; auto.
exists 1%Z; ring.
simpl in |- *; auto.
Qed.

Theorem EvenFNSuccFNSuccMid :
forall p : float,
Fbounded b p ->
FNeven b radix precision p ->
Fminus radix (FNSucc b radix precision (FNSucc b radix precision p))
(FNSucc b radix precision p) = Fminus radix (FNSucc b radix precision p) p
:>R.