Library UniMath.CategoryTheory.Categories.Type.Structures

Other structures in type_precat

Contents

  • Exponentials (Exponentials_Type)
    • The exponential functor y ↦ yˣ (exp_functor)
    • Exponentials (ExponentialsType)

Exponentials

Exponential functor


Section ExponentialFunctor.
  Context (A : UU).
This is the object we're ×-ing and ^-ing with
To show that type_precat has exponentials, we need a right adjoint to the functor Y ↦ X × Y for fixed Y.
  Local Definition exp_functor_ob (X : UU) : UU := A -> X.
  Local Definition exp_functor_arr (X Y : UU) (f : X -> Y) :
    (A -> X) -> (A -> Y) := λ g, f g.
  Local Definition exp_functor_data : functor_data type_precat type_precat :=
    functor_data_constr _ _ (exp_functor_ob : type_precat type_precat)
                            (@exp_functor_arr).

  Lemma exp_functor_is_functor : is_functor exp_functor_data.
  Proof.
    use make_dirprod.
    - intro; reflexivity.
    - intros ? ? ? ? ?; reflexivity.
  Defined.

  Definition exp_functor : functor type_precat type_precat :=
    make_functor exp_functor_data exp_functor_is_functor.
End ExponentialFunctor.