Zulip Chat Archive
Stream: new members
Topic: closure of a relation and equality of `Quot.mk`
Nicolas Rolland (Aug 02 2024 at 07:22):
Is there a proof that using equality of quotient, as defined by Quot.mk r
, is the closure of r ?
And thus obtain an existential serie of zig-zag..
My goal is to prove transport
below
import Mathlib.CategoryTheory.Category.Cat
universe u
namespace CategoryTheory
variable {C D : Cat}
variable {a b : C}
variable (F : C ⥤ D)
def isConnected (c : C ) (d : C) : Prop := ∃ _ : c ⟶ d, True
def refl_trans_symm_closure{α : Type u} (r : α → α → Prop) a b := Quot.mk r a = Quot.mk r b
def isConnectedByZigZag : C → C → Prop := refl_trans_symm_closure isConnected
lemma easytransport (h : isConnected a b) : isConnected (F.obj a) (F.obj b) := by
obtain ⟨f,_⟩ := h
exact ⟨F.map f, trivial⟩
lemma transport (h : isConnectedByZigZag a b) : isConnectedByZigZag (F.obj a) (F.obj b) := by
obtain x := h
sorry
end CategoryTheory
Kyle Miller (Aug 02 2024 at 07:25):
Yeah, take a look at docs#EqvGen and the theorems in that module.
Last updated: May 02 2025 at 03:31 UTC