#20769: LatticePoset: Orthocomplements, part 1
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Reporter: jmantysalo | Owner:
Type: enhancement | Status: needs_review
Priority: major | Milestone: sage-7.3
Component: combinatorics | Resolution:
Keywords: | Merged in:
Authors: Jori Mäntysalo | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
u/jmantysalo/orthocompletion | 51d4fd0e5ef01b019826b75f1ceb99603586ec18
Dependencies: | Stopgaps:
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Comment (by jmantysalo):
Replying to [comment:9 kdilks]:
> At last, I have time to look at things. Preliminary comments:
>
> * There should be some sort of definition as to what an orthocomplement
is.
More logical place would be in "interface part" in `lattices.py`, I think.
> * Correction to corner cases has a typo (ortohocomplement).
OK, I'll correct that.
> * This seems to be assuming that the elements of your poset are the
integers 1...n . Even if constructing the Hasse diagram ends up assigning
a labeling to the elements so the code works, it won't be clear to the
user what the output has to do with their original lattice.
Again, this should be on interface part (#20817). I think that we must
assume that a user reading docs for internal class like `HasseDiagram`
mostly knows what to do.
> * Orthocomplementations are only defined on complemented lattices. I'm
not sure if {{{is_complemented_lattice()}}} exists or is computationally
feasible (TODO?).
We do have `is_complemented` at `lattices.py`, and it is just `O(n^2)`
after computing the meets and joins (which is `O(n^2.5)`. But this
function detects non-selfdual lattices indirectly. (Btw, the code for
complements is broken at corner case, see #20727.)
--
Ticket URL: <http://trac.sagemath.org/ticket/20769#comment:10>
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