Zulip Chat Archive

Stream: mathlib4

Topic: Equiv.refl without argument


Martin Dvořák (Oct 21 2025 at 11:14):

Should there be an alternative to Equiv.refl that doesn't require explicit argument?
The way I deal with it is

notation "=.≃" => Equiv.refl _

but maybe there should be something for all Mathlib users.

Edward van de Meent (Oct 21 2025 at 18:07):

i made a PR like that once (adding Equiv.rfl and the like for a bunch of such structures) (#29118). the main reaction was "we probably don't want that for defs"

Aaron Liu (Oct 21 2025 at 18:11):

It could be a notation

Martin Dvořák (Oct 21 2025 at 18:18):

Edward van de Meent said:

i made a PR like that once (adding Equiv.rfl and the like for a bunch of such structures) (#29118). the main reaction was "we probably don't want that for defs"

It it about Equiv or Equivalence or both?

Edward van de Meent (Oct 21 2025 at 19:04):

ah, it's about things in the CategoryTheory corner, meaning CategoryTheory.Iso, CategoryTheory.Equivalence and similar. not Equiv. Still, i suspect that the issues raised aren't specific to categories

Martin Dvořák (Oct 21 2025 at 19:08):

I guess so. I simply love chaining the dot notation.


Last updated: Dec 20 2025 at 21:32 UTC