#3461: write a construction for permutation groups so that the coercion system
can
find a common parent
------------------------------+---------------------------------------------
Reporter: mhansen | Owner: joyner
Type: defect | Status: needs_review
Priority: minor | Milestone: sage-4.4.2
Component: group_theory | Keywords:
Author: Mike Hansen | Upstream: N/A
Reviewer: David Loeffler | Merged:
Work_issues: |
------------------------------+---------------------------------------------
Changes (by davidloeffler):
* reviewer: => David Loeffler
Comment:
The original patch suffered from a particularly evil piece of bitrotting:
since the patch was written, some change somewhere has meant that the
trivial permutation now has truth value True, not False, which meant that
the pushout code would never terminate -- it would keep on returning
bigger and bigger towers of (empty) construction functors!
The new patch I've just uploaded gets around this by using the
{{{is_one}}} method, instead of a plain truth value test. It passes
doctests under 4.4.1. Anyone willing to sign off on my tiny changes, and
maybe we can get this into Sage 5.0?
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/3461#comment:2>
Sage <http://www.sagemath.org>
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