Add canonical meetands

[jm58660]

For symmetry with #21597 after that has been closed.

CC: @tscrim

Component: combinatorics

Author: Jori Mäntysalo

Branch/Commit: cb7b710

Reviewer: Travis Scrimshaw

Issue created by migration from https://trac.sagemath.org/ticket/21601

[jm58660]

Branch: u/jmantysalo/add_canonical_meetands

[jm58660]

comment:2

Done this. The code is just a direct dual. To test try

n = 30; seed = 42; p = 0.999
set_random_seed(seed)
L = Posets.RandomLattice(n, p)
L_ = L.dual()
for e in L:
    if L.canonical_joinands(e) is None and L_.canonical_meetands(e) is None:
        continue
    if sorted(L.canonical_joinands(e)) != sorted(L_.canonical_meetands(e)):
        print("ERROR")
        break
else:
    print("OK")

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New commits:

cb7b710

Add canonical meetands.

[jm58660]

Commit: cb7b710

[tscrim]

comment:3

LGTM.

[tscrim]

Reviewer: Travis Scrimshaw

[vbraun]

Changed branch from u/jmantysalo/add_canonical_meetands to cb7b710