Create the category of SetsWithGrading

[Nicolas M. Thiéry]

The patch creates the category SetsWithGrading (with an example: non negative integers, graded by themselves) and puts WeightedIntegerVectors into this category.

See also: #10194

Apply:

• trac_10193-graded_sets-rebased.patch​
• trac_10193-graded_sets-review-ts.patch​

[Mike Hansen]

It seems like it would be better to use degree as opposed to size for consistency with the "standard" graded things. Also, it seems like it might be better to have the degree method implemented on the parents. It could be somewhat confusing if the degree method on the elements corresponded to a different grading than the parent it belongs to.

[Florent Hivert]

Hi ! What is the status of this one ?

[Paul Zimmermann]

Hi, here at SD35.5 I wanted to review #9280, but I see it depends on this ticket, which did not progress since 15 months. Is this ticket dead?

Paul

PS: moreover the patch url is dead...

[Nicolas M. Thiéry]

Replying to zimmerma:

Hi, here at SD35.5 I wanted to review #9280, but I see it depends on this ticket, which did not progress since 15 months. Is this ticket dead?

We just discussed it with Vincent Delecroix, and where planning to finalize/review it during the Sage-Combinat days in Cernay (early February).

PS: moreover the patch url is dead...

Should be fixed now.

[Travis Scrimshaw]

Hey Nicolas and Florent (and Vincent),

I was wondering what the status of this patch is since #13605 is currently based on this patch. I can commute #13605 past, but I would prefer to keep the current order (especially if this patch is close to being completed).

Thank you,
Travis

[Travis Scrimshaw]

Note that this will be swapped with #13605 in the combinat queue once Andrew uploads his review patch.

[Nicolas M. Thiéry]

TODO: add an example!

[Vincent Delecroix]

What's new:

• remove the changes for partitions as it affects #13605
• rename GradedSets to SetsWithGrading
• creation of an example (sage.categories.examples.sets_with_grading)
• fix documentation

Vincent

[Travis Scrimshaw]

Hey Vincent,

Let us know when the rebased patch over #6495 is up and ready for review.

Thanks,
Travis

[Vincent Delecroix]

Hey Travis,

Actually it is (in the sage-combinat queue). I wait for the review patch of Nicolas Borie !

Best, Vincent

[Frédéric Chapoton]

rebased on 5.8.beta4 (just a doc change)

apply trac_10193-graded_sets-rebased.patch

[Frédéric Chapoton]

There remains at least one self.n which has not been turned into a self._n

This makes a lot of tests fail.

[Vincent Delecroix]

Replying to chapoton:

There remains at least one self.n which has not been turned into a self._n

This makes a lot of tests fail.

You are right. I also notice that the comment message in the top of the patch file is not adapted to the content (the patch does not touch anymore Permutations).

[Frédéric Chapoton]

I have changed the .n and now tests should pass

[Frédéric Chapoton]

new patch, removing one assert statement

[Travis Scrimshaw]

Hey,

A few comments/questions:

• I prefer the name GradedSets over SetsWithGrading, it's a more natural name to me.
• The example, I don't think there should be the need for another NonNegativeIntegers class. Can't we just use the existing sage.sets.NonNegativeIntegers with the required methods and placed in this category?
• Similar to above, I'd like to see all sets which belong actually into this category. Or at least a few more of the big classes.
• Grade should be implemented as an abstract Element method
• I don't like the default implementation of graded_component() since it assumes the first argument of subset (which may not be implemented) is the graded component. If you want to use the subset() method, you should call it with self.subset(grade=grade).
• It's not well documented what methods must be implemented. The "automatic" way is to make them @abstract_methods.

Here's also some more wish-list type things that I'd like to see, but can wait for a followup ticket:

• Simple API for grading shifts
• Checking that morphisms preserve grading
• Make degree() call grade() (thus act like an alias, unfortunately in categories you can't simply make an alias by degree = grade [it will reference the wrong function]).

Thanks,
Travis

[Travis Scrimshaw]

I just talked with Nicolas T. and basically my previous comments are to be disregarded except the documentation of the methods which need to be implemented needs to be improved.

Best,
Travis

[Nicolas M. Thiéry]

Replying to tscrim:

I just talked with Nicolas T. and basically my previous comments are to be disregarded except the documentation of the methods which need to be implemented needs to be improved.

I should add that those objections were natural! It would be good to explain in the documentation why SetsWithGrading? rather than GradedSets?. But this patch has been waiting long enough and it needs to be finally be put to real use; let's not delay it for this reason.

+1 as well on the feature requests in a later patch! (except for degree=grade for which I'd rather wait until we have some large scale feedback to see if there really would be a desire for it).

[Travis Scrimshaw]

Here's a review patch which describes what needs to be implemented and some other minor doc fixes. If you're happy with the changes, you can set this to positive review.

Best,
Travis

For patchbot:

Apply: trac_10193-graded_sets-rebased.patch trac_10193-graded_sets-review-ts.patch

[Vincent Delecroix]

Hi,

Thanks Travis. I am not happy!! The last sentence of the documentation of the category is uncomprehensible and there should be a link to the example.

I will upload an ultimate patch in a minute...

Vincent

[Vincent Delecroix]

It also appears that the example was not included in the documentation...

Apply: trac_10193-graded_sets-rebased.patch trac_10193-graded_sets-review-ts.patch trac_10193-graded_sets-more_doc-vd.patch

[Travis Scrimshaw]

Hey Vincent,

I've folded your review patch in and made changes to that (very) poorly written sentence I wrote.

Best,
Travis

For patchbot:

Apply: trac_10193-graded_sets-rebased.patch trac_10193-graded_sets-review-ts.patch

[Vincent Delecroix]

Hi Travis,

I've folded your review patch in and made changes to that (very) poorly written sentence I wrote.

Perfect! I am not sure it was yours (and your english is for sure better than mine). I remember the first time I learn how to do a parent and a category: I found useful when they were specifications and pointers ! Best Vincent