mathlib4 chore(Data/List): Depend less on big operators

Make Data.List.Count, Data.List.Dedup, Data.List.ProdSigma, Data.List.Range, Data.List.Rotate, Data.List.Zip not depend on Data.List.BigOperators.Basic.
As a consequence, move the big operators lemmas that were in there to Data.List.BigOperators.Basic. For the lemmas that were Nat-specific, keep a version of themin the original file but stated using Nat.sum.
To help with this, add Nat.sum_eq_listSum (l : List Nat) : Nat.sum l = l.sum.

Mar 28 '24 11:03 YaelDillies

To me this is a second-order concern: the primary concern is to stop algebra, order theory and finiteness from leaking into each other (this PR is specifically concerned about the algebra → finiteness leak, can you believe we need rings to define finite sets!). Organising each sublibrary is tomorrow's job, not today's.

Concretely, this means:

These lemmas have to move. They can't stay where they are because they concern algebra but are in finiteness files.
Data.List.BigOperators.Basic is a mess, but already was before, and it's not really this PR's job to make the situation better.

There are avenues to improve Data.List.BigOperators.Basic in the future:

Delete Data.List.BigOperators.Lemmas (this is the infamous "too much import for Basic" file every folder has)
Instead have files graded according to the algebra imports they need. Something like this would be much better than what we have now:
- Monoid/group lemmas
- Ring lemmas
- Funkier stuff
Move the order stuff to a new Algebra.Order.BigOperators.List file (this is already done in #11725)

I could improve the situation in this PR but that would increase the diff.

Mar 28 '24 16:03 YaelDillies

I suppose this PR indeed makes things strictly better than the current situation. Unfortunately my laptop is broken so I can't test that everything ended up moved correctly. @fpvandoorn, would you like to assign yourself and finish the review?

On 28 March 2024 17.53.17 CET, "Yaël Dillies" @.***> wrote:

To me this is a second-order concern: the primary concern is to stop algebra, order theory and finiteness from leaking into each other (this PR is specifically concerned about the algebra → finiteness leak, can you believe we need rings to define finite sets!). Organising each sublibrary is tomorrow's job, not today's.

Concretely, this means:

These lemmas have to move. They can't stay where they are because they concern algebra but are in finiteness files.

Data.List.BigOperators.Basic is a mess, but already was before, and it's not really this PR's job to make the situation better.

There are avenues to improve Data.List.BigOperators.Basic in the future:

Delete Data.List.BigOperators.Lemmas (this is the infamous "too much import for Basic" file every folder has)

Instead have files graded according to the algebra imports they need. Something like this would be much better than what we have now:

Monoid/group lemmas

Ring lemmas

Funkier stuff

Move the order stuff to a new Algebra.Order.BigOperators.List file (this is already done in #11725)

I could improve the situation in this PR but that would increase the diff.

-- Reply to this email directly or view it on GitHub: https://github.com/leanprover-community/mathlib4/pull/11741#issuecomment-2025680801 You are receiving this because you were assigned.

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Mar 30 '24 09:03 Vierkantor

Thanks!

bors merge bors d+

Mar 31 '24 00:03 fpvandoorn

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

Mar 31 '24 00:03 mathlib-bors[bot]

Pull request successfully merged into master.

Build succeeded:

Mar 31 '24 02:03 mathlib-bors[bot]