#14541: Family over enumerated set has wrong category
-------------------------------------+-------------------------------------
Reporter: cnassau | Owner: nthiery
Type: defect | Status: needs_work
Priority: minor | Milestone: sage-6.4
Component: categories | Resolution:
Keywords: Family, Category | Merged in:
of finite enumerated sets, |
CartesianProduct |
Authors: Christian Nassau, | Reviewers:
Nathann Cohen |
Report Upstream: N/A | Work issues:
Branch: u/ncohen/14541 | Commit:
| fd3d6d51a3251999e327cf18c38f3389b2ee2a1b
Dependencies: | Stopgaps: wrongAnswerMarker
-------------------------------------+-------------------------------------
Changes (by jakobkroeker):
* stopgaps: => wrongAnswerMarker
Old description:
> This happens with Sage 5.10beta3:
>
> {{{
> sage: P=Permutations()
> sage: print P.category()
> Category of sets
> sage: print P.cardinality()
> +Infinity
> sage: F=Family(Permutations(), lambda i:i)
> sage: print F.category()
> Category of finite enumerated sets
> }}}
>
> But clearly {{{F}}} is not finite...
>
> Another bug, (also fixed in the attached patch):
> {{{
> sage: Family(CartesianProduct(ZZ,ZZ),lambda (x,y) :
> (x+y,x-y)).cardinality()
> ...
> TypeError: cardinality does not fit into a Python int.
> }}}
New description:
This happens with Sage 5.10beta3:
{{{
sage: P=Permutations()
sage: print P.category()
Category of sets
sage: print P.cardinality()
+Infinity
sage: F=Family(Permutations(), lambda i:i)
sage: print F.category()
Category of finite enumerated sets
}}}
But clearly {{{F}}} is not finite...
Another bug, (also fixed in the attached patch):
{{{
sage: Family(CartesianProduct(ZZ,ZZ),lambda (x,y) :
(x+y,x-y)).cardinality()
...
TypeError: cardinality does not fit into a Python int.
}}}
update: following example is still wrong (see second comment)
{{{
sage: X=CombinatorialFreeModule(ZZ,ZZ)
sage: print X
Free module generated by Integer Ring over Integer Ring
sage: print X.basis().category()
Category of enumerated sets
sage: TX = tensor((X,))
sage: print TX.basis().cardinality()
+Infinity
sage: print TX.basis().category()
Category of finite enumerated sets
}}}
--
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Ticket URL: <https://trac.sagemath.org/ticket/14541#comment:17>
Sage <http://www.sagemath.org>
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