Local Notation "'un'" := (@orp _).

Lemma ll_spooky x y z s1 s2 s1' s2' s : lseg (env_get (stk s1) x) (expr_denote y s1) (hp s1) -> lseg (env_get (stk s1') x) (expr_denote z s1') (hp s1') -> join_sub s1 s2 -> join_sub s1' s2' -> join s2 s2' s -> (pure_atom_denote (Eqv (Var x) y) || pure_atom_denote (Eqv (Var x) z))%pred s.