Skip to content

Commit

Permalink
Merge pull request #1907 from Alizter/ps/rr/i_indexed_coproducts_in_p…
Browse files Browse the repository at this point in the history
…type

I-indexed coproducts in pType
  • Loading branch information
Alizter authored Apr 13, 2024
2 parents 9da8c91 + cff20ad commit 0b1f8fd
Showing 1 changed file with 39 additions and 6 deletions.
45 changes: 39 additions & 6 deletions theories/Homotopy/Wedge.v
Original file line number Diff line number Diff line change
Expand Up @@ -194,14 +194,14 @@ Proof.
exact pt.
Defined.

Definition fwedge_in' (I : Type) (X : I -> pType)
: forall i, X i $-> FamilyWedge I X
:= fun i => Build_pMap _ _ (fun x => pushl (i; x)) (pglue i).

(** We have an inclusion map [pushl : sig X -> FamilyWedge X]. When [I] is pointed, so is [sig X], and then this inclusion map is pointed. *)
Definition fwedge_in (I : pType) (X : I -> pType)
: psigma (pointed_fam X) $-> FamilyWedge I X.
Proof.
snrapply Build_pMap.
- exact pushl.
- exact (pglue pt).
Defined.
: psigma (pointed_fam X) $-> FamilyWedge I X
:= Build_pMap _ _ pushl (pglue pt).

(** Recursion principle for the wedge of an indexed family of pointed types. *)
Definition fwedge_rec (I : Type) (X : I -> pType) (Z : pType)
Expand Down Expand Up @@ -230,6 +230,39 @@ Proof.
- exact pconst.
Defined.

Global Instance hasallcoproducts_ptype : HasAllCoproducts pType.
Proof.
intros I X.
snrapply Build_Coproduct.
- exact (FamilyWedge I X).
- exact (fwedge_in' I X).
- exact (fwedge_rec I X).
- intros Z f i.
snrapply Build_pHomotopy.
1: reflexivity.
simpl.
apply moveL_pV.
apply equiv_1p_q1.
symmetry.
exact (Pushout_rec_beta_pglue Z _ (unit_name pt) (fun i => point_eq (f i)) _).
- intros Z f g h.
snrapply Build_pHomotopy.
+ snrapply Pushout_ind.
* intros [i x].
nrapply h.
* intros [].
exact (point_eq _ @ (point_eq _)^).
* intros i; cbn.
nrapply transport_paths_FlFr'.
lhs nrapply concat_p_pp.
apply moveR_pV.
rhs nrapply concat_pp_p.
apply moveL_pM.
symmetry.
exact (dpoint_eq (h i)).
+ reflexivity.
Defined.

(** ** The pinch map on the suspension *)

(** Given a suspension, there is a natural map from the suspension to the wedge of the suspension with itself. This is known as the pinch map.
Expand Down

0 comments on commit 0b1f8fd

Please sign in to comment.