Braid group creates elements in wrong class

[miguelmarco]

Right now we have this inconsistency.

sage: B=BraidGroup(4)
sage: b=B([1,2,3])
sage: type(b)
<class 'sage.groups.braid.Braid'>
sage: type(b*b)
<class 'sage.groups.braid.BraidGroup_class_with_category.element_class'>

Both should be in the same class.

CC: @vbraun

Component: group theory

Keywords: braid

Author: Miguel Marco

Branch/Commit: 446e41d

Reviewer: Vincent Delecroix

Issue created by migration from https://trac.sagemath.org/ticket/16458

[miguelmarco]

Branch: u/mmarco/ticket/16458

[sagetrac-git]

Commit: 4e332f3

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

4e332f3

Changed `_element_constructor_` on Braid groups

[videlec]

comment:3

Hello Miguel,

The TestSuite is here to detect this kind of things...

sage: B = BraidGroup(3)
sage: TestSuite(B).run()

The tests are run on elements that are obtained from the method an_element or some_elements. Right now it uses a generic method which does not rely on _element_constructor_. But as you can see (with the old version)

sage: TestSuite(B([1,2])).run()
Traceback (most recent call last):
...
The following tests failed: _test_category

Please, implement in BraidGroup_class:

• a method an_element that return a braid
• a method some_elements that return some braids (built in different ways)
  And then put the TestSuite test in the __init__.

Vincent

[sagetrac-git]

Changed commit from 4e332f3 to e77666a

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

e77666a

Added an_element, some_elements and a TestSuite doctest to braid groups

[miguelmarco]

comment:5

Thanks, Vincent, done.

[videlec]

comment:7

Great. Just a little typo: you wrote EXAMMPLES instead of EXAMPLES.

[sagetrac-git]

Changed commit from e77666a to 446e41d

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

446e41d

Corrected typo

[videlec]

comment:9

Thanks

Vincent

[videlec]

Reviewer: Vincent Delecroix

[videlec]

Author: ​Miguel Marco

[videlec]

Changed keywords from none to braid

[vbraun]

Changed author from ​Miguel Marco to Miguel Marco

[vbraun]

comment:11

Invisible space deleted...

[vbraun]

Changed branch from u/mmarco/ticket/16458 to 446e41d