(** *** A proof via [pcofix]  To define the [paco] versions of [eqone] and [eqtwo], we apply the two constructors [paco1_2_0] and [paco1_2_1], respectively ("1" because we are dealing with unary predicates).  Again, the translation of the lemma and of its proof is almost trivial. *)
Definition eqtwo' t := paco1_2_1 eqone_gen eqtwo_gen bot1 bot1 t.
Hint Unfold eqone' eqtwo'.

(* Specifications: *)
Lemma eqone_gen_mon: monotone1_2 eqone_gen. Proof. pmonauto. Qed.
Lemma eqtwo_gen_mon: monotone1_2 eqtwo_gen. Proof. pmonauto. Qed.
Hint Resolve eqone_gen_mon eqtwo_gen_mon : paco.
Lemma eqone'_eins: eqone' eins.
Section safety.