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