#14703: Bad error message when Finitely Presented Group cannot be represented as
pemrutation groups
--------------------------------+-------------------------------------------
Reporter: Bouillaguet | Owner: joyner
Type: defect | Status: new
Priority: major | Milestone: sage-5.11
Component: group theory | Resolution:
Keywords: | Work issues:
Report Upstream: N/A | Reviewers:
Authors: | Merged in:
Dependencies: | Stopgaps:
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Description changed by Bouillaguet:
Old description:
> {{{
> sage: G.<a,b> = FreeGroup()
> sage: H = G / [a^3*b]
> sage: H.as_permutation_group()
> ---------------------------------------------------------------------------
> UnboundLocalError Traceback (most recent call
> last)
> ...
> UnboundLocalError: local variable 'l' referenced before assignment
> }}}
New description:
{{{
sage: G.<a,b> = FreeGroup()
sage: H = G / [a^3*b]
sage: H.as_permutation_group()
---------------------------------------------------------------------------
UnboundLocalError Traceback (most recent call
last)
...
UnboundLocalError: local variable 'l' referenced before assignment
}}}
The problem is that the group is in fact infinite (and thus cannot be
represented as a permutation group). This should be handled more
graciously...
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Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/14703#comment:1>
Sage <http://www.sagemath.org>
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