(** * Being inhabited *)

(** The predicate [inhabited] can be used in different contexts. If [A] is
    thought as a type, [inhabited A] states that [A] is inhabited. If [A] is
    thought as a computationally relevant proposition, then
    [inhabited A] weakens [A] so as to hide its computational meaning.
    The so-weakened proof remains computationally relevant but only in
    a propositional context.
*)

Inductive inhabited (A:Type) : Prop := inhabits : A -> inhabited A.(** * Being inhabited *)

(** The predicate [inhabited] can be used in different contexts. If [A] is
    thought as a type, [inhabited A] states that [A] is inhabited. If [A] is
    thought as a computationally relevant proposition, then
    [inhabited A] weakens [A] so as to hide its computational meaning.
    The so-weakened proof remains computationally relevant but only in
    a propositional context.
*)

Inductive inhabited (A:Type) : Prop := inhabits : A -> inhabited A.

Lemma exists_inhabited : forall (A:Type) (P:A->Prop), (exists x, P x) -> inhabited A.