Opened 3 years ago

Closed 3 years ago

#21481 closed enhancement (fixed)

Poset documentation polishing: Polynomials

Reported by: jmantysalo Owned by:
Priority: minor Milestone: sage-7.4
Component: documentation Keywords:
Cc: kdilks Merged in:
Authors: Jori Mäntysalo Reviewers: Frédéric Chapoton
Report Upstream: N/A Work issues:
Branch: 1a4eab1 (Commits) Commit: 1a4eab125f5412ac68c8208cb285184322c68522
Dependencies: Stopgaps:

Description

This contains one minimal code change: order_polynomial now uses as_ideals=False, which is clearly (but only slightly) faster.

Mostly I just unified wordings from "self" to "the poset", make expectations always to be a second paragraph ("The poset is expected to be bounded and ranked.") moved some trivial EXAMPLES to TESTS and added spaces to examples.

This continues the serie of #18925, #18941, #18959, #19141, #19360, #19435, #21197.

Change History (11)

comment:1 Changed 3 years ago by jmantysalo

  • Branch set to u/jmantysalo/poset-polynomials

comment:2 Changed 3 years ago by jmantysalo

  • Cc kdilks added
  • Commit set to 84e7d0f5c8d90846be8ecc2ef7b91c6fb878870c
  • Component changed from PLEASE CHANGE to documentation
  • Priority changed from major to minor
  • Status changed from new to needs_info
  • Type changed from PLEASE CHANGE to enhancement

Kevin: I think that there is another way to look at chain_polynomial(), some vector of poset. That is, something we got with .chain_polynomial().coefficients(). I think it should be mentioned, but now I forgot the name. Do you remember it?


New commits:

84e7d0fDocstring modifications.

comment:3 Changed 3 years ago by chapoton

expacted

comment:4 Changed 3 years ago by git

  • Commit changed from 84e7d0f5c8d90846be8ecc2ef7b91c6fb878870c to e35373f15cee7655aa63f3e6e351779f2fc19268

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

e35373fA typo.

comment:5 Changed 3 years ago by kdilks

Was it related to enumerating linear extensions by enumerating the number of saturated, strict chains in the lattice of order ideals?

comment:6 follow-up: Changed 3 years ago by chapoton

polynomial is SageMath

comment:7 Changed 3 years ago by jmantysalo

Found it. It is f-vector of a poset, see for example http://www.lehigh.edu/~mas906/papers/defense.ps. I suppose it is worth mentioning, as the question "What integer sequences are f-vector for some poset?" has got attention, and it seems to be never formulated as "What polynomials can are chain polynomial for some poset?".

comment:8 Changed 3 years ago by git

  • Commit changed from e35373f15cee7655aa63f3e6e351779f2fc19268 to 1a4eab125f5412ac68c8208cb285184322c68522

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

1a4eab1Typo; add mention of f-vector.

comment:9 in reply to: ↑ 6 Changed 3 years ago by jmantysalo

  • Status changed from needs_info to needs_review

Replying to chapoton:

polynomial is SageMath

Thanks. This is now also corrected.

comment:10 Changed 3 years ago by chapoton

  • Reviewers set to Frédéric Chapoton
  • Status changed from needs_review to positive_review

let it be.

comment:11 Changed 3 years ago by vbraun

  • Branch changed from u/jmantysalo/poset-polynomials to 1a4eab125f5412ac68c8208cb285184322c68522
  • Resolution set to fixed
  • Status changed from positive_review to closed
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