Hi Rob!
On Sep 21, 2:15 am, Rob Beezer <goo...@beezer.cotse.net> wrote:
> sage: g = Graph()
> sage: g.add_vertices(Subsets(3,2))
> sage: g.vertices()
> [{2, 3}, {1, 2}, {1, 3}]
> sage: sorted(g.vertices())
> [{1, 3}, {1, 2}, {2, 3}]
> sage: Subsets(3,2).list()
> [{1, 2}, {1, 3}, {2, 3}]
> sage: sorted(Subsets(3,2).list())
> [{2, 3}, {1, 3}, {1, 2}]
I think the problem is that there is no proper ordering defined for
sage.sets.set.Set_object_enumerated:
sage: S = Subsets(3,2).list()[0]
sage: T = Subsets(3,2).list()[1]
sage: S
{1, 2}
sage: T
{1, 3}
sage: type(S)
<class 'sage.sets.set.Set_object_enumerated'>
sage: S < T
True
sage: T < S
True
sage: S==T
False
So, unless someone implements __cmp__ (or similar) methods for
Set_object_enumerated, you can't expect to get anything meaningful out
of the sorting.
Best regards,
Simon
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