ASKSAGE: Sage Q&A Forum - RSS feedhttps://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Fri, 19 Nov 2021 18:04:06 +0100Group algebra of permutation group, errorhttps://ask.sagemath.org/question/59837/group-algebra-of-permutation-group-error/Why does not
GroupAlgebra(PermutationGroup([(1,2,3),(2,3,4)]),QQ).center_basis()
work when
GroupAlgebra(AlternatingGroup(4),QQ).center_basis()
does work?
The first command gives a long error message, terminating with the slightly bizzare
RuntimeError: There is a bug in the coercion code in Sage.
Both x (=()) and y (=()) are supposed to have identical parents but they don't.
In fact, x has parent 'Permutation Group with generators [(2,3,4), (1,2,3)]'
whereas y has parent 'Permutation Group with generators [(2,3,4), (1,2,3)]'
Original elements () (parent Permutation Group with generators [(2,3,4), (1,2,3)]) and () (parent Permutation Group with
generators [(2,3,4), (1,2,3)]) and maps
<class 'NoneType'> None
<class 'sage.structure.coerce_maps.DefaultConvertMap_unique'> (map internal to coercion system -- copy before use)
Coercion map:
From: Permutation Group with generators [(2,3,4), (1,2,3)]
To: Permutation Group with generators [(2,3,4), (1,2,3)]Fri, 19 Nov 2021 16:24:51 +0100https://ask.sagemath.org/question/59837/group-algebra-of-permutation-group-error/Comment by Max Alekseyev for <p>Why does not</p>
<pre><code>GroupAlgebra(PermutationGroup([(1,2,3),(2,3,4)]),QQ).center_basis()
</code></pre>
<p>work when</p>
<pre><code>GroupAlgebra(AlternatingGroup(4),QQ).center_basis()
</code></pre>
<p>does work?</p>
<p>The first command gives a long error message, terminating with the slightly bizzare</p>
<pre><code>RuntimeError: There is a bug in the coercion code in Sage.
Both x (=()) and y (=()) are supposed to have identical parents but they don't.
In fact, x has parent 'Permutation Group with generators [(2,3,4), (1,2,3)]'
whereas y has parent 'Permutation Group with generators [(2,3,4), (1,2,3)]'
Original elements () (parent Permutation Group with generators [(2,3,4), (1,2,3)]) and () (parent Permutation Group with
generators [(2,3,4), (1,2,3)]) and maps
<class 'NoneType'> None
<class 'sage.structure.coerce_maps.DefaultConvertMap_unique'> (map internal to coercion system -- copy before use)
Coercion map:
From: Permutation Group with generators [(2,3,4), (1,2,3)]
To: Permutation Group with generators [(2,3,4), (1,2,3)]
</code></pre>
https://ask.sagemath.org/question/59837/group-algebra-of-permutation-group-error/?comment=59839#post-id-59839It says it's a bug. So it needs to be reported.Fri, 19 Nov 2021 18:04:06 +0100https://ask.sagemath.org/question/59837/group-algebra-of-permutation-group-error/?comment=59839#post-id-59839