#13749: IntegerListsLex has finite issues
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Reporter: tscrim | Owner: sage-combinat
Type: defect | Status: new
Priority: major | Milestone: sage-5.6
Component: combinatorics | Resolution:
Keywords: finite sets, integer lists | Work issues:
Report Upstream: N/A | Reviewers:
Authors: | Merged in:
Dependencies: #13605 | Stopgaps:
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Changes (by tscrim):
* dependencies: => #13605
Old description:
> `IntegerListsLex` has some issues with finiteness:
> {{{
> sage: L = IntegerListsLex(NonNegativeIntegers(), max_length=3,
> ceiling=lamabda i: 3)
> sage: L
> Integer lists of sum in <class
> 'sage.sets.non_negative_integers.NonNegativeIntegers'> satisfying certain
> constraints
> sage: for x in L:
> ....:
> []
> [1]
> [0, 1]
> [0, 0, 1]
> ...
> [3, 3, 2]
> [3, 2, 3]
> [2, 3, 3]
> [3, 3, 3]
> # Continues looping for forever (which I guess is okay)
> sage: L.is_finite()
> # Loops for forever
> sage: L.category()
> Category of sets
>
> sage: L2 = IntegerListsLex(NonNegativeIntegers(), max_length=3)
> sage: L2.is_finite()
> # Loops for forever
> sage: L2.category()
> Category of sets
> }}}
> The last two are not correct, and this would likely need moderate
> checking of combinations of the input arguments.
New description:
`IntegerListsLex` has some issues with finiteness:
{{{
sage: L = IntegerListsLex(NonNegativeIntegers(), max_length=3,
ceiling=lamabda i: 3)
sage: L
Integer lists of sum in <class
'sage.sets.non_negative_integers.NonNegativeIntegers'> satisfying certain
constraints
sage: for x in L:
....:
[]
[1]
[0, 1]
[0, 0, 1]
...
[3, 3, 2]
[3, 2, 3]
[2, 3, 3]
[3, 3, 3]
# Continues looping for forever (which I guess is okay)
sage: L.is_finite()
True
sage: L.category()
Category of finite enumerated sets
sage: L2 = IntegerListsLex(NonNegativeIntegers(), max_length=3)
sage: L2.is_finite()
True
sage: L2.category()
Category of finite enumerated sets
}}}
The last two are not correct, and this would likely need moderate checking
of combinations of the input arguments.
--
Comment:
Without #13605 applied, the `is_finite()` loops for forever and the
category is just `The category of sets`.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/13749#comment:2>
Sage <http://www.sagemath.org>
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