Skip to content

[Merged by Bors] - feat(Data/Polynomial/Derivation): add version of chain rule - #7419

Closed
rmhi wants to merge 20 commits into
masterfrom
eval2-chain-rule
Closed

[Merged by Bors] - feat(Data/Polynomial/Derivation): add version of chain rule#7419
rmhi wants to merge 20 commits into
masterfrom
eval2-chain-rule

Conversation

@rmhi

@rmhi rmhi commented Sep 28, 2023

Copy link
Copy Markdown
Collaborator

If A is an R-algebra and d : A → M is a derivation, then for any polynomial f : R[X] and any a : A,
d(f(a)) = f'(a) d a.


There are shorter proofs of this result, but in my view the most sensible proof is to interpret both sides of
the equation as derivations R[X] \to M, and then to check that they agree in the case f = X.

Open in Gitpod

@rmhi rmhi added the awaiting-CI This PR does not pass CI yet. This label is automatically removed once it does. label Sep 28, 2023
@github-actions github-actions Bot removed the awaiting-CI This PR does not pass CI yet. This label is automatically removed once it does. label Sep 28, 2023
Comment thread Mathlib/Data/Polynomial/Derivation.lean Outdated
Comment thread Mathlib/Data/Polynomial/Derivation.lean Outdated
Comment thread Mathlib/Data/Polynomial/Derivation.lean Outdated
Comment thread Mathlib/Data/Polynomial/Derivation.lean Outdated
@jcommelin jcommelin added awaiting-author A reviewer has asked the author a question or requested changes. and removed awaiting-review labels Oct 12, 2023
@rmhi rmhi added awaiting-review and removed awaiting-author A reviewer has asked the author a question or requested changes. labels Oct 14, 2023
@rmhi
rmhi requested a review from riccardobrasca October 15, 2023 19:41
@riccardobrasca

Copy link
Copy Markdown
Member

Can you split the PR in two, opening another one with only the R[X]-module structure? It is an important construction (thanks for adding it!) and it deserves its own discussion. Feel free to ask my review.

@rmhi rmhi added blocked-by-other-PR This PR depends on another PR (this label is automatically managed by a bot) and removed awaiting-review labels Oct 17, 2023
@ghost ghost removed the blocked-by-other-PR This PR depends on another PR (this label is automatically managed by a bot) label Oct 17, 2023
bors Bot pushed a commit that referenced this pull request Nov 1, 2023
…map. (#7728)

Given an element `a` in an `R`-algebra `A` and an `A`-module `M`,
define an `R[X]`-module `Module.AEval R M a`, whose elements correspond to
elements of `M`, and where the action of `f : R[X]` is `f • m = aeval a f • m`. 
Equivalently, `X • m = a • m`.

This module is abbreviated to `Module.AEval' φ` in the special case that `A` is the algebra of `R`-linear maps and `φ : M → M` is an `R`-linear map.

This is needed in #7419.



Co-authored-by: Richard M. Hill <86743862+rmhi@users.noreply.github.com>
Co-authored-by: Eric Wieser <wieser.eric@gmail.com>
@ghost ghost added the merge-conflict The PR has a merge conflict with master, and needs manual merging. (this label is managed by a bot) label Nov 1, 2023
@rmhi rmhi added the awaiting-author A reviewer has asked the author a question or requested changes. label Nov 2, 2023
@jcommelin jcommelin added the awaiting-author A reviewer has asked the author a question or requested changes. label Nov 3, 2023
rmhi and others added 2 commits November 3, 2023 10:25
Comment thread Mathlib/Data/Polynomial/Derivation.lean Outdated
@rmhi rmhi added awaiting-review and removed awaiting-author A reviewer has asked the author a question or requested changes. labels Nov 3, 2023
@jcommelin

Copy link
Copy Markdown
Member

bors d+

@bors

bors Bot commented Nov 3, 2023

Copy link
Copy Markdown

✌️ rmhi can now approve this pull request. To approve and merge a pull request, simply reply with bors r+. More detailed instructions are available here.

@github-actions github-actions Bot added delegated This pull request has been delegated to the PR author (or occasionally another non-maintainer). and removed awaiting-review labels Nov 3, 2023
@jcommelin

Copy link
Copy Markdown
Member

In fact, this seems completely ready for merging, so:

Thanks 🎉

bors merge

@github-actions github-actions Bot added the ready-to-merge This PR has been sent to bors. label Nov 3, 2023
@eric-wieser

eric-wieser commented Nov 3, 2023

Copy link
Copy Markdown
Member

This will have conflicts with #8151, as the name of the simps lemma changes.

bors Bot pushed a commit that referenced this pull request Nov 3, 2023
If `A` is an `R`-algebra and `d : A → M` is a derivation, then for any polynomial `f : R[X]` and any `a : A`,
`d(f(a)) = f'(a) d a`.



Co-authored-by: Richard M. Hill <86743862+rmhi@users.noreply.github.com>
@eric-wieser

Copy link
Copy Markdown
Member

bors r-

@bors

bors Bot commented Nov 3, 2023

Copy link
Copy Markdown

Canceled.

@rmhi

rmhi commented Nov 3, 2023

Copy link
Copy Markdown
Collaborator Author

This will have conflicts with #8151, as the name of the simps lemma changes.

If I change the name from toFun to apply on line 150, then I assume this will be ok, except that the code will not work until #8151 is merged. How should I proceed?

@eric-wieser

eric-wieser commented Nov 3, 2023

Copy link
Copy Markdown
Member

Yes, if you make that change I'm happy for you to put this on the queue even though CI will fail; as you say, it will succeed when it lands.

@eric-wieser

Copy link
Copy Markdown
Member

Alternatively, if you wait 5 minutes you can just merge master :)

@eric-wieser

Copy link
Copy Markdown
Member

bors merge

bors Bot pushed a commit that referenced this pull request Nov 3, 2023
If `A` is an `R`-algebra and `d : A → M` is a derivation, then for any polynomial `f : R[X]` and any `a : A`,
`d(f(a)) = f'(a) d a`.



Co-authored-by: Richard M. Hill <86743862+rmhi@users.noreply.github.com>
Co-authored-by: Eric Wieser <wieser.eric@gmail.com>
@ocfnash

ocfnash commented Nov 3, 2023

Copy link
Copy Markdown
Contributor

GitHub was flaking and bors crashed so we need to try this again

bors merge

bors Bot pushed a commit that referenced this pull request Nov 3, 2023
If `A` is an `R`-algebra and `d : A → M` is a derivation, then for any polynomial `f : R[X]` and any `a : A`,
`d(f(a)) = f'(a) d a`.



Co-authored-by: Richard M. Hill <86743862+rmhi@users.noreply.github.com>
Co-authored-by: Eric Wieser <wieser.eric@gmail.com>
@bors

bors Bot commented Nov 3, 2023

Copy link
Copy Markdown

Pull request successfully merged into master.

Build succeeded!

The publicly hosted instance of bors-ng is deprecated and will go away soon.

If you want to self-host your own instance, instructions are here.
For more help, visit the forum.

If you want to switch to GitHub's built-in merge queue, visit their help page.

@bors bors Bot changed the title feat(Data/Polynomial/Derivation): add version of chain rule [Merged by Bors] - feat(Data/Polynomial/Derivation): add version of chain rule Nov 3, 2023
@bors bors Bot closed this Nov 3, 2023
@bors
bors Bot deleted the eval2-chain-rule branch November 3, 2023 21:31
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Labels

delegated This pull request has been delegated to the PR author (or occasionally another non-maintainer). ready-to-merge This PR has been sent to bors.

Projects

None yet

Development

Successfully merging this pull request may close these issues.

5 participants