Bug in trivial abelian group

[chriswuthrich]

The following code

K.<t> = NumberField(x^2+17)
I = K.ideal(3,t+1)
S = K.primes_above(11)
A = K.S_class_group(S)
A(I)

produces the error

TypeError: unsupported operand parent(s) for '*': 'Ambient free module
of rank 1 over the principal ideal domain Integer Ring' and 'Full
MatrixSpace of 0 by 0 dense matrices over Integer Ring'

The same error can be obtained by

A.identity()

The problem seems to arise only when the abelian group is trivial.

I imagine this is not a problem of the class group implementation, but one of (trivial) abelian group.

Component: group theory

Keywords: S-class group, trivial abelian group

Reviewer: Chris Wuthrich

Issue created by migration from https://trac.sagemath.org/ticket/11843

[chriswuthrich]

comment:1

This is no longer a problem in 5.9. This ticket can be closed now:

sage: K.<t> = NumberField(x^2+17)
sage: I = K.ideal(3,t+1)
sage: S = K.primes_above(11)
sage: A = K.S_class_group(S)
sage: A(I)
Trivial S-ideal class
sage: A.identity()
Trivial S-ideal class

(Sorry that I can't remember what to do with a ticket like this. I just put it to need_review ...

[chriswuthrich]

comment:2

... and then to positive_review). Sorry if I do the wrong thing. In any case the ticket can be closed without further action.

[jdemeyer]

Reviewer: Chris Wuthrich