(** ** Definition *)

Inductive nd := intu | class.(** ** Definition *)

Inductive nd := intu | class.(** ** Definition *)

Inductive nd := intu | class.Notation "A ⊢C phi" := (@prv class _ A phi) (at level 30).Definition prv_min := @prv intu frag.Definition prv_class := @prv class full.Definition prv_intu := @prv intu full.(** ** Soundness *)


Definition cast {domain} (eta eta' : nat -> domain) (I : interp eta) : interp eta'.

Lemma sat_ext_p b (phi : form b) dom rho rho' eta eta' (I : interp dom eta) : (forall v, rho v = rho' v) -> (forall p, p el consts phi -> eta p = eta' p) -> sat I rho phi <-> sat (cast eta' I) rho' phi.