(** *** 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 eqone' t := paco1_2_0 eqone_gen eqtwo_gen bot1 bot1 t.Definition eqtwo' t := paco1_2_1 eqone_gen eqtwo_gen bot1 bot1 t.

Lemma eqone'_eins: eqone' eins.