#18757: Poset catalog: Element type of BooleanLattice, IntegerCompositions and
IntegerPartitions
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Reporter: jmantysalo | Owner:
Type: defect | Status: needs_info
Priority: minor | Milestone: sage-wishlist
Component: combinatorics | Resolution:
Keywords: posets | Merged in:
Authors: Jori Mäntysalo | Reviewers:
Report Upstream: N/A | Work issues:
Branch: u/jmantysalo/int- | Commit:
compositions-lattice | 3cbece29ca9b586055a78f1f7a14de3441c67be8
Dependencies: | Stopgaps:
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Changes (by {'newvalue': u'Jori M\xe4ntysalo', 'oldvalue': ''}):
* status: new => needs_info
* commit: => 3cbece29ca9b586055a78f1f7a14de3441c67be8
* cc: chapoton, ncohen (added)
* author: => Jori Mäntysalo
Comment:
It is clear that `IntegerCompositions` should not return just a poset but
a lattice. However, I have two real questions:
1) Should it be possible to return only poset when asked? It does not make
any difference for `PentagonPoset()`, but `BooleanLattice(10)` is totally
different thing. OTOH we could have functions that directly fill meet- and
join-matrix when creating these special types of lattice. Or we could have
some way to generate a lattice by trusting input and compute meet and join
when they are first asked.
2) Should (almost) all poset examples have a parameter to tell what kind
of elements it should have? Spesifically, if we find a direct way to make
a lattice isomorphic to, say, `TamariLattice(n)`, we could save some
computation time.
Attached patch shows what this could look like.
Bonus question: If answer to one or both is "yes", what should be the name
of the parameter?
----
New commits:
||[http://git.sagemath.org/sage.git/commit/?id=3cbece29ca9b586055a78f1f7a14de3441c67be8
3cbece2]||{{{Modifications for IntegerCompositions.}}}||
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Ticket URL: <http://trac.sagemath.org/ticket/18757#comment:3>
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