#15456: fix bug in has_right/left_descents in Weyl group code
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Reporter: | Owner:
zabrocki | Status: needs_review
Type: | Milestone: sage-6.2
defect | Resolution:
Priority: major | Merged in:
Component: | Reviewers:
combinatorics | Work issues:
Keywords: | Commit:
Authors: | 549f238c87e446116457d645c2b0171b423c02df
Frédéric Chapoton | Stopgaps:
Report Upstream: N/A |
Branch: |
u/chapoton/15456 |
Dependencies: |
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Comment (by tscrim):
Replying to [comment:12 chapoton]:
> I do not understand why my solution is not good enough. From my point of
view, the function `has_descent` in `weyl_group.py` should rather be named
`has_right_descent`, because it is necessary to have at least one of the
two (left or right) descent methods to avoid the infinite loop. I think
that `has_descent` should only be defined for abstract Coxeter groups.
The `has_descent()` in `weyl_group.py` works for both sides, and by simply
doing an alias, you're exposing invalid (at least 'should not be used')
arguments in `has_right_descent()`. In essence what you're doing is saying
`has_right_descent()` should call `has_descent()` with the appropriate
arguments. I'm saying let's do this in a generic fashion to follow the
spec (I think comment:4 point 1 is in the doc already, but I haven't
checked).
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Ticket URL: <http://trac.sagemath.org/ticket/15456#comment:14>
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