Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

feat(ring_theory/ideals): quotient rings #196

Merged
merged 7 commits into from
Jul 17, 2018

Conversation

ChrisHughes24
Copy link
Member

Quotient rings are a ring, quotient by prime ideal is an integral domain, and quotient by maximal ideal is a field (noncomputable).

@@ -3,15 +3,44 @@ Copyright (c) 2018 Kenny Lau. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Authors: Kenny Lau
Copy link
Member

@kbuzzard kbuzzard Jul 15, 2018

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

add Chris Hughes.

Thanks Chris by the way -- I need this for perfectoids!


lemma mul_left {S : set α} [is_ideal S] : b ∈ S → a * b ∈ S := @is_submodule.smul α α _ _ _ _ a _

lemma mul_right {S : set α} [is_ideal S] : a ∈ S → a * b ∈ S := mul_comm b a ▸ mul_left
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

At least zero, add and sub should be protected here.


/- quotient by maximal ideal is a field. def rather than instance, since users will have
computable inverses in some applications -/
noncomputable def field (S : set α) [is_maximal_ideal S] : field (quotient S) :=
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

this should also be protected

@digama0 digama0 merged commit 980a01e into leanprover-community:master Jul 17, 2018
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
None yet
Projects
None yet
Development

Successfully merging this pull request may close these issues.

None yet

3 participants