Section PACO_METATHEORY.
Context {D : Type} {PROSET : isProset D}.
#[local] Hint Resolve le_join_lattice_introl le_join_lattice_intror join_lattice_le_intro bot_lattice_le_intro : core.

Lemma strong_coinduction {COLA : isCola D} {UPPER_LATTICE : isUpperSemilattice D} (f : `[D -> D]) (x : D)
: x =< proj1_sig (nu f) <-> x =< proj1_sig f (join_lattice x (proj1_sig (nu f))).