#21069: comparison of permutation and list: unexpected result
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Reporter: dkrenn | Owner:
Type: defect | Status: new
Priority: major | Milestone: sage-7.3
Component: coercion | Resolution:
Keywords: | Merged in:
Authors: | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
Dependencies: | Stopgaps:
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Changes (by tscrim):
* cc: sage-combinat, darij (added)
Comment:
I think this is more an issue with the default `_cmp_` in `ClonableArray`
wanting to have a common parent, but there are not coercions between most
combinatorial objects (nor should there be typically). IMO, this is even
worse:
{{{
sage: Permutations([1])[0] == Permutation([1])
False
}}}
However, I don't agree with the argument that "same representation =>
equality". Should the partition `[2, 1]` equal the permutation `[2, 1]`?
(Currently they do, but I think that is a small issue and you should not
rely on this behavior.) We run into a major notation problem as there is
not enough valid syntax and math notation to separate the two clearly;
context (or their parents) separate them.
--
Ticket URL: <https://trac.sagemath.org/ticket/21069#comment:1>
Sage <http://www.sagemath.org>
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