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Implement Fock space #15508

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tscrim opened this issue Dec 11, 2013 · 104 comments
Closed

Implement Fock space #15508

tscrim opened this issue Dec 11, 2013 · 104 comments

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@tscrim
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tscrim commented Dec 11, 2013

In type A. I put this in a new algebras/quantum_groups folder in preparation of Lie algebras and quantum groups #14901.

Depends on #25067

CC: @sagetrac-sage-combinat @AndrewAtLarge @anneschilling @bsalisbury1

Component: algebra

Keywords: Fock space quantum group representations

Author: Travis Scrimshaw

Branch/Commit: b4f73fa

Reviewer: Andrew Mathas

Issue created by migration from https://trac.sagemath.org/ticket/15508

@AndrewMathas
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comment:2

Hi Travis,

Thanks for both working on this and for letting me know about it. I just had a quick glance through it and it looks very nice, but there is a lot of code to digest! The fact that the new improved git-world makes it difficult to separate the current ticket from its dependencies makes this harder of course. I will try and look through this properly in due course as it is one of the things that I care about - and implementing this was on my to-do list.

A few questions/comments (based on my very quick read through):

  • I noticed that you have implemented Fayer's LLT algorithm for computing the canonical bases of the combinatorial Fock spaces. I haven't looked at all at the details of your code but in his paper Fayers' has a conjecture for the degrees of the polynomials that came up (they should always be less than the defect/weight), and he mentioned that if this conjecture were true then there are some shortcuts which speed up his algorithm. Fayers' conjecture is now known to be true, so I was wondering whether you have used this in your code.

  • Am I right in thinking that you have only implemented the Fock spaces F(\Lambda) such that F(\Lambda)\cong F(\Lambda_{a_1})\otimes\dots\otimes F(\Lambda_{a_k}), for dominant weights \Lambda=\Lambda_{a_1}+\dots+\Lambda_{a_k}?

    In addition to these "standard" Fock spaces there are some more general Fock spaces for U_q(\widehat{sl}_e) defined by Uglov. I am asking this more for information/clarification as Uglov's Fock spaces don't come up in my work - they arise in the cateogorification of rational Cherednik algebras.

  • In terms of displaying the elements of the Fock space I think that

  |[3, 1]> + q*|[2, 2]> + q^ 2*|[2, 1, 1]>

is too cumbersome. I would prefer something like

  |3, 1> + q*|2, 2> + q^ 2*|2, 1, 1>

and something similar for higher levels. Other alternatives would be

  F(3, 1) + q*F(2, 2) + q^ 2*F(2, 1, 1)

or

  F([3, 1]) + q*F([2, 2]) + q^ 2*F([2, 1, 1])

which both have the distinct advantage that you can cut and paste the output back into sage (for a suitably defined shortcut F).

Cheers,
Andrew

@tscrim
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tscrim commented Dec 11, 2013

comment:3

Hey Andrew,

Replying to @AndrewAtLarge:

Thanks for both working on this and for letting me know about it. I just had a quick glance through it and it looks very nice, but there is a lot of code to digest! The fact that the new improved git-world makes it difficult to separate the current ticket from its dependencies makes this harder of course.

Actually, there's not a functional dependency on #15289, just some syntax, so I can commute this past with relative ease if #15289 doesn't get reviewed before we are done with this.

I will try and look through this properly in due course as it is one of the things that I care about - and implementing this was on my to-do list.

A few questions/comments (based on my very quick read through):

  • [I]n his paper Fayers' has a conjecture for the degrees of the polynomials that came up (they should always be less than the defect/weight), ... Fayers' conjecture is now known to be true, so I was wondering whether you have used this in your code.

No I do not. Currently I don't check if a partition is regular, so I guess I'm really computing for the full tensor product space. I should also note another abuse; my indexing set for the highest weight modules is too large (I'm using all partitions instead of just the n-regular and giving an error when the user tries to create a non-n-regular partition). I probably should change that...
>.>
<.<

  • Am I right in thinking that you have only implemented the Fock spaces F(\Lambda) such that F(\Lambda)\cong F(\Lambda_{a_1})\otimes\dots\otimes F(\Lambda_{a_k}), for dominant weights \Lambda=\Lambda_{a_1}+\dots+\Lambda_{a_k}?

Correct.

In addition to these "standard" Fock spaces there are some more general Fock spaces for U_q(\widehat{sl}_e) defined by Uglov. I am asking this more for information/clarification as Uglov's Fock spaces don't come up in my work - they arise in the cateogorification of rational Cherednik algebras.

Hmm...interesting. Do you have a reference I could look at?

  • In terms of displaying ... I would prefer something like
  |3, 1> + q*|2, 2> + q^ 2*|2, 1, 1>

and something similar for higher levels.

I will make this change along with restricting the indexing set to the proper set.

Best,

Travis

@sagetrac-vbraun-spam sagetrac-vbraun-spam mannequin modified the milestones: sage-6.0, sage-6.1 Dec 17, 2013
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tscrim commented Dec 27, 2013

Changed dependencies from #15289 to #15289 #15525

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sagetrac-git mannequin commented Dec 27, 2013

Changed commit from 4548a5b to 1daad96

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sagetrac-git mannequin commented Dec 27, 2013

Branch pushed to git repo; I updated commit sha1. New commits:

1daad96Changes to term formatting and restricted some indexing sets.
f5a794bMerge branch 'public/combinat/partitions_constraints-15525' into public/modules/fock_space
1adb368Added deprecation to IntegerListLex global_options arg. Fixed doctests.
2341248Merge branch 'public/combinat/partitions_constraints-15525' into public/modules/fock_space
4143c96Merge branch 'develop' into public/combinat/partitions_constraints-15525
976a4d1Merge branch 'public/combinat/partitions_constraints-15525' into public/modules/fock_space
82d7b6fMerge branch 'master' into public/modules/fock_space
7982d3aIniital fix and added regular partitions.
3597354Merge branch 'master' into public/modules/fock_space

@tscrim
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tscrim commented Dec 27, 2013

comment:7

I still need to restrict the indices for the general HW representations.

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sagetrac-git mannequin commented Jan 2, 2014

Branch pushed to git repo; I updated commit sha1. New commits:

ac31208Fixed indexing set and doctest.
2eaee1bConverted to the proper indexing set for HW repr.
772c09bMerge branch 'public/combinat/regular_partition_tuples' into public/modules/fock_space
12f1d6bAdded regular partition tuples.

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sagetrac-git mannequin commented Jan 2, 2014

Changed commit from 1daad96 to ac31208

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sagetrac-git mannequin commented Jan 2, 2014

Changed commit from ac31208 to 62afb1b

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sagetrac-git mannequin commented Jan 2, 2014

Branch pushed to git repo; I updated commit sha1. New commits:

62afb1bAdded TODO message for HW repr.

@tscrim
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tscrim commented Jan 2, 2014

Changed dependencies from #15289 #15525 to #15289 #15525 #15621

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tscrim commented Jan 2, 2014

comment:10

What does the Fock say? It goes #15621 and back to needs review. :p

@sagetrac-vbraun-spam sagetrac-vbraun-spam mannequin modified the milestones: sage-6.1, sage-6.2 Jan 30, 2014
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sagetrac-git mannequin commented Mar 4, 2014

Branch pushed to git repo; I updated commit sha1. Last 10 new commits:

991953aMerge branch 'develop' into public/monoids/15289-indexed
b51bc3dMerge branch 'public/monoids/15289-indexed' into public/modules/fock_space
f13f9adMerge branch 'develop' into public/modules/fock_space
bd82ed8Merge branch 'develop' into public/monoids/15289-indexed
56703ebMade Indexed* have entry points through Free*.
163df6eChanged more _basis_keys to _indices, deprecated the former.
8db8e0aChanged `_an_element_` to indexed_monoid.py.
760c939Merge branch 'public/monoids/15289-indexed' of trac.sagemath.org:sage into public/monoids/15289-indexed
03057a4Merge branch 'develop' into public/monoids/15289-indexed
d2f6254Merge branch 'public/monoids/15289-indexed' into public/modules/fock_space

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sagetrac-git mannequin commented Mar 4, 2014

Changed commit from 62afb1b to d2f6254

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sagetrac-git mannequin commented Mar 13, 2014

Changed commit from d2f6254 to 9fe7ae7

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sagetrac-git mannequin commented Mar 13, 2014

Branch pushed to git repo; I updated commit sha1. New commits:

a2996e0Merge branch 'develop' into public/monoids/15289-indexed
9fe7ae7Merge branch 'public/monoids/15289-indexed' into public/modules/fock_space

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sagetrac-git mannequin commented Nov 15, 2017

Branch pushed to git repo; I updated commit sha1. New commits:

407c806Merge branch 'public/modules/fock_space' in 8.1.rc0

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sagetrac-git mannequin commented Nov 15, 2017

Changed commit from c101a33 to 407c806

@fchapoton
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comment:64
  • typo "agianst"

  • could we "lazy import" this new things ?

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sagetrac-git mannequin commented Nov 20, 2017

Branch pushed to git repo; I updated commit sha1. New commits:

8e50781Merge branch 'public/modules/fock_space' of git://trac.sagemath.org/sage into public/modules/fock_space
c6aec4aFixed typo.

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sagetrac-git mannequin commented Nov 20, 2017

Changed commit from 407c806 to c6aec4a

@tscrim
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tscrim commented Nov 20, 2017

comment:66

Replying to @fchapoton:

  • typo "agianst"

Fixed.

  • could we "lazy import" this new things ?

The only thing added to the global namespace is FockSpace, which is lazily imported. The quantum_groups/all.py file is not, but IMO, that should not be lazily imported (and we do not do that anywhere else).

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sagetrac-git mannequin commented Mar 31, 2018

Changed commit from c6aec4a to a898d44

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sagetrac-git mannequin commented Mar 31, 2018

Branch pushed to git repo; I updated commit sha1. New commits:

67c6ba0Adding q-analogs used in quantum groups.
a898d44Merge branch 'public/modules/fock_space' of git://trac.sagemath.org/sage into public/modules/fock_space

@tscrim
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tscrim commented Mar 31, 2018

comment:68

Trivial rebase having split off the q-numbers to a separate ticket.

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tscrim commented Mar 31, 2018

Dependencies: #25067

@tscrim tscrim modified the milestones: sage-8.1, sage-8.2 Mar 31, 2018
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sagetrac-git mannequin commented Mar 31, 2018

Changed commit from a898d44 to f4bba3e

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sagetrac-git mannequin commented Mar 31, 2018

Branch pushed to git repo; I updated commit sha1. New commits:

e908d59Adding q-analogs used in quantum groups.
f4bba3eMerge branch 'public/quantum_groups/q_numbers-25067' into public/modules/fock_space

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sagetrac-git mannequin commented Apr 30, 2018

Changed commit from f4bba3e to b4f73fa

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sagetrac-git mannequin commented Apr 30, 2018

Branch pushed to git repo; I updated commit sha1. New commits:

b4f73faMinor tweaks to documentation

@AndrewMathas
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comment:71

The code looks good. I have made a few minor tweaks to the documentation and changed the hi method to the more descriptive h_inverse. If you are happy with these, and all tests pass, then please consider this a positive review.

@tscrim
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tscrim commented Apr 30, 2018

Reviewer: Andrew Mathas

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tscrim commented Apr 30, 2018

comment:73

Thank you very much.

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vbraun commented May 14, 2018

Changed branch from public/modules/fock_space to b4f73fa

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