lots of cleanup

[coq-hetmet.git] / src / GeneralizedArrowCategory.v

diff --git a/src/GeneralizedArrowCategory.v b/src/GeneralizedArrowCategory.v
index 974fdc3..7d8b20b 100644 (file)
--- a/src/GeneralizedArrowCategory.v
+++ b/src/GeneralizedArrowCategory.v
@@ -23,7 +23,81 @@ Require Import Coherence_ch7_8.
 Require Import Enrichment_ch2_8.
 Require Import RepresentableStructure_ch7_2.
 Require Import GeneralizedArrow.
+Require Import WeakFunctorCategory.
+Require Import SmallSMMEs.
 
-Definition CategoryOfGeneralizedArrows : Category SMME (fun x y => @GeneralizedArrow x _ y).
-  admit.
-  Qed.
+(*
+ * Technically reifications form merely a *semicategory* (no identity
+ * maps), but one can always freely adjoin identity maps (and nothing
+ * else) to a semicategory to get a category whose non-identity-map
+ * portion is identical to the original semicategory
+ *
+ * Also, technically this category has ALL enrichments (not just the
+ * surjective monic monoidal ones), though there maps OUT OF only the
+ * surjective enrichments and INTO only the monic monoidal
+ * enrichments.  It's a big pain to do this in Coq, but sort of might
+ * matter in real life: a language with really severe substructural
+ * restrictions might fail to be monoidally enriched, meaning we can't
+ * use it as a host language.  But that's for the next paper...
+ *)
+Inductive GeneralizedArrowOrIdentity : SMMEs -> SMMEs -> Type :=
+  | gaoi_id   : forall smme:SMMEs,                             GeneralizedArrowOrIdentity smme smme
+  | gaoi_ga : forall s1 s2:SMMEs, GeneralizedArrow s1 s2  -> GeneralizedArrowOrIdentity s1   s2.
+
+Definition generalizedArrowOrIdentityFobj (s1 s2:SMMEs) (f:GeneralizedArrowOrIdentity s1 s2) : s1 -> s2 :=
+  match f in GeneralizedArrowOrIdentity S1 S2 return S1 -> S2 with
+  | gaoi_id  s       => fun x => x
+  | gaoi_ga s1 s2 f  => fun a => ehom(ECategory:=s2) (mon_i (smme_mon s2)) (ga_functor_obj f a)
+  end.
+
+Definition generalizedArrowOrIdentityFunc s1 s2 (f:GeneralizedArrowOrIdentity s1 s2)
+  : Functor s1 s2 (generalizedArrowOrIdentityFobj _ _ f) :=
+  match f with
+  | gaoi_id  s       => functor_id _
+  | gaoi_ga s1 s2 f  => ga_functor f >>>> HomFunctor s2 (mon_i s2)
+  end.
+
+Definition compose_generalizedArrows (s0 s1 s2:SMMEs) :
+  GeneralizedArrow s0 s1 -> GeneralizedArrow s1 s2 -> GeneralizedArrow s0 s2.
+  intro g01.
+  intro g12.
+  refine
+    {| ga_functor          := g01 >>>> HomFunctor s1 (mon_i s1) >>>> g12 |}.
+    apply MonoidalFunctorsCompose.
+    apply MonoidalFunctorsCompose.
+    apply (ga_functor_monoidal g01).
+    apply (me_mf s1).
+    apply (ga_functor_monoidal g12).
+    Defined.
+
+Definition generalizedArrowOrIdentityComp
+  : forall s1 s2 s3, GeneralizedArrowOrIdentity s1 s2 -> GeneralizedArrowOrIdentity s2 s3 -> GeneralizedArrowOrIdentity s1 s3.
+  intros.
+  destruct X.
+    apply X0.
+  destruct X0.
+    apply (gaoi_ga _ _ g).
+    apply (gaoi_ga _ _ (compose_generalizedArrows _ _ _ g g0)).
+    Defined.
+
+Definition MorphismsOfCategoryOfGeneralizedArrows : @SmallFunctors SMMEs.
+  refine {| small_func      := GeneralizedArrowOrIdentity
+          ; small_func_id   := fun s => gaoi_id s
+          ; small_func_func := fun smme1 smme2 f => generalizedArrowOrIdentityFunc _ _ f
+          ; small_func_comp := generalizedArrowOrIdentityComp
+         |}; intros; simpl.
+  apply if_id.
+  destruct f as [|fobj f]; simpl in *.
+    apply if_inv.
+    apply if_left_identity.
+  destruct g as [|gobj g]; simpl in *.
+    apply if_inv.
+    apply if_right_identity.
+  unfold mf_F.
+  idtac.
+  unfold mf_f.
+  apply if_associativity.
+  Defined.
+
+Definition CategoryOfGeneralizedArrows :=
+  WeakFunctorCategory MorphismsOfCategoryOfGeneralizedArrows.