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Lie algebras #14901

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tscrim opened this issue Jul 17, 2013 · 84 comments
Open

Lie algebras #14901

tscrim opened this issue Jul 17, 2013 · 84 comments

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@tscrim
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tscrim commented Jul 17, 2013

Initial implementation of Lie algebras in sage.

This will contain the following:

  • Free Lie algebras
    • Hall basis
    • Lyndon basis
  • Abelian Lie algebras
  • Lie algebras from an associative algebra
  • Lie algebras from structure coefficients
  • Finite type Lie algebras
    • As matrices for types ABCD
    • In the Chevalley basis
  • gln
  • Untwisted affine Lie algebras constructed from a finite type
  • Untwisted affine Kac-Moody Lie algebras (i.e. the above and the Lie derivative)
  • Universal enveloping algebras
    • PBW bases
  • Quotient, sub, and direct sum Lie algebras and Lie algebra ideals
  • Other examples:
    • Upper triangular matrices
    • Strictly upper triangular matrices
    • Heisenberg algebra
    • Witt algebra
    • Virasoro algebra
    • Some nilpotent Lie algebras
  • Kac-Moody algebras based only on a (generalized) Cartan matrix
  • Lie algebra (co)homology
  • Chargeless and Verma modules for the Virasoro algebra
  • Fock space
  • sun

There might also be the following:

  • recovery of Lie group from Lie algebra (Nilpotent Lie groups #26344 for nilpotent Lie groups)
  • connection between the quantum group and the Hall algebra (coming from representations of a quiver over Fq)

With this, one will be able to do basic computations, as well as compute things such as the lower central series (depending on the type).

Current ticket breakdown (more might follow):

Bug tickets: #25007, #25008, #33836, #34006

Quantum group tickets:

Other related tickets:

Nilpotent Lie algebras tickets:

Depends on #16824
Depends on #16826

CC: @sagetrac-sage-combinat @anneschilling @nthiery @darijgr @bsalisbury1 @dwbump @simon-king-jena

Component: algebra

Keywords: Lie algebras, Kac Moody, days54, fpsac2019

Author: Travis Scrimshaw

Branch/Commit: public/algebras/lie_algebras-14901 @ b8bcd7d

Issue created by migration from https://trac.sagemath.org/ticket/14901

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tscrim commented Jul 20, 2013

comment:4

Other (poosible) additions:

  • LLT basis and Fock spaces for Uq(sln) (arbitrary g?)
  • implementation of the quantum group
  • connection between the quantum group and the Hall algebra (coming from representations of a quiver over Fq)
  • recovery of Lie group from Lie algebra (where it makes sense)
  • PBW(-type) bases of universal enveloping algebra (quantum group)
  • canonical bases of quantum groups

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darijgr commented Jul 20, 2013

comment:5

That's a hell of a project!

At some point, when linear algebra works in combinatorial free modules, I'll want (and probably make) the Lie algebra of primitives of a Hopf algebra.

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tscrim commented Aug 3, 2013

Changed dependencies from #10963 to #10963 #14898

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tscrim commented Aug 3, 2013

comment:6

I'm currently setting #14898 as a dependency since that will likely be done before this patch and because they should play together.

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tscrim commented Sep 3, 2013

Changed dependencies from #10963 #14898 to #10963 #14898 #15151

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tscrim commented Sep 3, 2013

comment:7

For defining the action on Fock space needs #15151.

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tscrim commented Oct 16, 2013

Changed dependencies from #10963 #14898 #15151 to #10963 #14898 #15151 #15289

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tscrim commented Oct 16, 2013

comment:8

To do PBW(-type) bases, I'll need #15289.

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tscrim commented Nov 5, 2013

Attachment: trac_14901-lie_algebras-ts.patch.gz

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tscrim commented Nov 5, 2013

comment:9

Okay, here's the current version of the patch for reference for those don't want to get/use the combinat queue. It does about 80% or so of the functionality I want, but it probably could use some restructuring. It's also missing a lot of documentation (most importantly doctests). Here's what's done and (mostly) working:

  • Free Lie algebras in the Hall basis
  • The Lyndon basis for the free Lie algebra
  • Abelian Lie algebras
  • Lie algebras from an associative algebra
  • Lie algebras from structure coefficients
  • Finite type Lie algebras
    • As matrices for types ABCD
    • In the Chevalley basis
  • gln
  • The Lie algebra of strictly upper triangular matrices
  • The Lie algebra of upper triangular matrices
  • Untwisted affine Lie algebras constructed from a finite type
  • Untwisted affine Kac-Moody Lie algebras (i.e. the above and the Lie derivative) [done]
  • Universal enveloping algebras
  • Kac-Moody algebras based only on a (generalized) Cartan matrix
  • LLT basis and Fock spaces for Uq(sln) [done]
  • PBW(-type) bases of universal enveloping algebra (quantum group) [done for Lie algebras up to abstracting internal structure]
  • canonical bases of quantum groups [90% done]
  • the Heisenberg Lie algebras and some other misc examples
  • quotient, sub, and direct sum Lie algebras and Lie algebra ideals [doesn't always seem to reduce properly]

Everything else:

  • twisted affine Lie and Kac-Moody algebras via loop groups/diagram automorphims [I want to do this, but haven't started and might push to a later ticket]
  • the Goodman and Wenzl modified LLT algorithm [haven't started yet]
  • polynomial representations for sln [doesn't give the correct results]
  • implementation of quantum groups [65% done]
  • connection between the quantum group and the Hall algebra (coming from representations of a quiver over Fq) [I would need to understand Hall algebras better to do this]
  • sun [possibly to be dropped as the Sage infrastructure does not seem to be there]
  • recovery of Lie group from Lie algebra (where it makes sense) [0% done, likely to be dropped]

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tscrim commented Nov 8, 2013

Changed dependencies from #10963 #14898 #15151 #15289 to #10963 #14898 #15151 #15289 #15384

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tscrim commented Nov 8, 2013

Branch: public/algebras/lie_algebras-14901

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sagetrac-git mannequin commented Nov 8, 2013

Commit: 9d33268

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sagetrac-git mannequin commented Nov 8, 2013

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

[9d33268](https://github.com/sagemath/sagetrac-mirror/commit/9d33268)#14901: Initial implementation of Lie algebras.
[db19b7c](https://github.com/sagemath/sagetrac-mirror/commit/db19b7c)Merge branch 'public/monoids/15289-indexed' into public/algebras/lie_algebras-14901
[643bfcb](https://github.com/sagemath/sagetrac-mirror/commit/643bfcb)Merge branch 'public/combinat/root_systems/improvements' into public/algebras/lie_algebras-14901
[362fd5e](https://github.com/sagemath/sagetrac-mirror/commit/362fd5e)# Tue Oct 29 20:14:19 2013 +0100
[b2914f3](https://github.com/sagemath/sagetrac-mirror/commit/b2914f3)# Sun Oct 27 13:58:49 2013 +0100
[9d9cae3](https://github.com/sagemath/sagetrac-mirror/commit/9d9cae3)# Sat Oct 19 11:50:04 2013 +0200
[0251a33](https://github.com/sagemath/sagetrac-mirror/commit/0251a33)Trac #13394: Implement faster and safer WeakValueDictionary
[c1b5afe](https://github.com/sagemath/sagetrac-mirror/commit/c1b5afe)#15289: Implemented indexed monoids and groups.
[6fd33b2](https://github.com/sagemath/sagetrac-mirror/commit/6fd33b2)#15169: Fix FreeAlgebra element constructor from a base field.
[0fa598a](https://github.com/sagemath/sagetrac-mirror/commit/0fa598a)imported patch root_system_data-ts.patch

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tscrim commented Nov 9, 2013

Changed keywords from Lie algebras Kac Moody to Lie algebras Kac Moody, days54

@kcrisman
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comment:13

You might find this link interesting and relevant. Apparently this person implemented quite a bit...

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tscrim commented Nov 13, 2013

comment:14

Replying to @kcrisman:

You might find this link interesting and relevant. Apparently this person implemented quite a bit...

Thanks. That has the branching rules and operations on the algebras themselves, which is useful, than doing computations within them.

Also as a reference for myself: http://coropa.sourceforge.net/

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sagetrac-git mannequin commented Nov 18, 2013

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

[658e41d](https://github.com/sagemath/sagetrac-mirror/commit/658e41d)Merge branch 'master' into public/algebras/lie_algebras-14901

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sagetrac-git mannequin commented Nov 18, 2013

Changed commit from 9d33268 to 658e41d

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sagetrac-git mannequin commented Nov 19, 2013

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

[efecd11](https://github.com/sagemath/sagetrac-mirror/commit/efecd11)Fixes to printing of PBW basis elements.
[eec85ad](https://github.com/sagemath/sagetrac-mirror/commit/eec85ad)Merge branch 'public/combinat/root_systems/improvements-15384' into public/algebras/lie_algebras-14901
[b4c7865](https://github.com/sagemath/sagetrac-mirror/commit/b4c7865)Merge branch 'master' into public/combinat/root_systems/improvements-15384
[e40f892](https://github.com/sagemath/sagetrac-mirror/commit/e40f892)Changed horizontal to basic_untwisted.
[930782b](https://github.com/sagemath/sagetrac-mirror/commit/930782b)Fixed indentation error.
[f87789d](https://github.com/sagemath/sagetrac-mirror/commit/f87789d)Merge branch 'master' into public/combinat/root_systems/improvements-15384

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sagetrac-git mannequin commented Nov 19, 2013

Changed commit from 658e41d to efecd11

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sagetrac-git mannequin commented Dec 3, 2013

Changed commit from efecd11 to 4466b12

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sagetrac-git mannequin commented Dec 3, 2013

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

[4466b12](https://github.com/sagemath/sagetrac-mirror/commit/4466b12)Merge branch 'public/monoids/15289-indexed' into public/algebras/lie_algebras-14901
[9dca526](https://github.com/sagemath/sagetrac-mirror/commit/9dca526)Added comparison operations.
[a493bee](https://github.com/sagemath/sagetrac-mirror/commit/a493bee)Merge branch 'master' into public/monoids/15289-indexed

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@tscrim tscrim modified the milestones: sage-8.1, sage-8.2 Mar 20, 2018
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@tscrim tscrim modified the milestones: sage-8.2, sage-8.3 Apr 13, 2018
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videlec commented Aug 3, 2018

comment:53

update milestone 8.3 -> 8.4

@videlec videlec modified the milestones: sage-8.3, sage-8.4 Aug 3, 2018
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ehaka mannequin commented Aug 17, 2018

comment:55

Added a subsection of tickets related to various constructions related to nilpotent Lie algebras. I have some existing implementations for these in a codebase that needs to be cleaned up and refactored in order to be imported to Sage.

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tscrim commented Jul 10, 2019

Changed keywords from Lie algebras, Kac Moody, days54 to Lie algebras, Kac Moody, days54, fpsac2019

@tscrim tscrim removed this from the sage-8.4 milestone Jul 10, 2019
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tscrim commented Jun 17, 2022

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