#5664: Bugs in PermutationGroup_subgroup.__cmp__
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Reporter: SimonKing | Owner: SimonKing
Type: defect | Status: new
Priority: critical | Milestone: sage-3.4.1
Component: group_theory | Keywords: comparison subgroup
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Comment(by SimonKing):
Hi,
Replying to [comment:3 wdj]:
> Based on how I think mathematicians would most likely use this, I'm in
favor of 1.
>
> In any case, I don't agree that "with 1., == would test whether K and H
are isomorphic abstract groups". The code is
>
> {{{
> if not isinstance(right, PermutationGroup_generic):
> return -1
> return right._gap_().__cmp__(self._gap_())
> }}}
> which seems to be a wrapper for GAP's equality. Does that seem right to
you?
Right. My (apparently wrong) assumption was that gap tests for
isomorphism.
So, my reason for supporting 1. broke.
However, who did implement (I guess overloaded) the `__cmp__` method of
PermutationGroup_generic for PermutationGroup_subgroup? What was the
original reason for taking into account the ambient group?
Cheers,
Simon
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/5664#comment:4>
Sage <http://sagemath.org/>
Sage - Open Source Mathematical Software: Building the Car Instead of
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