Opened 3 years ago
Closed 3 years ago
#24725 closed enhancement (fixed)
Make power poset a meet-semilattice
Reported by: | jmantysalo | Owned by: | |
---|---|---|---|
Priority: | minor | Milestone: | sage-8.2 |
Component: | combinatorics | Keywords: | |
Cc: | tscrim | Merged in: | |
Authors: | Jori Mäntysalo | Reviewers: | Frédéric Chapoton |
Report Upstream: | N/A | Work issues: | |
Branch: | 6d0bd62 (Commits, GitHub, GitLab) | Commit: | 6d0bd62e5e71c3b635e3838eea94d480ad1bfb99 |
Dependencies: | Stopgaps: |
Description
Power poset is meet-semilattice, of course -- meet of elements is the "intersection" of posets.
Change History (8)
comment:1 Changed 3 years ago by
- Branch set to u/jmantysalo/power-lattice
comment:2 Changed 3 years ago by
- Cc tscrim added
- Commit set to 6d0bd62e5e71c3b635e3838eea94d480ad1bfb99
- Status changed from new to needs_review
comment:3 follow-up: ↓ 4 Changed 3 years ago by
Ok, looks good. Is this poset selfdual, or not ?
Is the PowerPoset
the same as the picture on page 8 of
https://arxiv.org/pdf/1701.07995.pdf
?
comment:4 in reply to: ↑ 3 Changed 3 years ago by
Replying to chapoton:
Ok, looks good. Is this poset selfdual, or not ?
Is the
PowerPoset
the same as the picture on page 8 ofhttps://arxiv.org/pdf/1701.07995.pdf
?
No, this is different thing. Elements of this poset are posets. The bottom element is the antichain on elements 1..n
(actually 0..n-1
), and maximal elements are all n!
chains.
comment:5 Changed 3 years ago by
- Reviewers set to Frédéric Chapoton
- Status changed from needs_review to positive_review
ok, then
comment:6 follow-up: ↓ 7 Changed 3 years ago by
Wouldn't it be good to add a line to the doc explaining why it is a semilattice?
comment:7 in reply to: ↑ 6 Changed 3 years ago by
Replying to mantepse:
Wouldn't it be good to add a line to the doc explaining why it is a semilattice?
It would.
Volker doesn't like modifying tickets already in positive review, so I will combine this with some other changes.
comment:8 Changed 3 years ago by
- Branch changed from u/jmantysalo/power-lattice to 6d0bd62e5e71c3b635e3838eea94d480ad1bfb99
- Resolution set to fixed
- Status changed from positive_review to closed
New commits:
Return type of PowerPoset().