Fix 0/0 in ore function field

[kliem]

sage: k.<a> = GF(5^2)
sage: Frob = k.frobenius_endomorphism()
sage: der = k.derivation(a, twist=Frob)
sage: S.<x> = k['x', der]
sage: K = S.fraction_field()
sage: K(0)/K(0)
0

CC: @xcaruso

Component: algebra

Author: Jonathan Kliem

Branch/Commit: 192b564

Reviewer: Markus Wageringel, Xavier Caruso

Issue created by migration from https://trac.sagemath.org/ticket/32109

[kliem]

Branch: public/32109

[kliem]

Commit: 9e53965

[kliem]

New commits:

9e53965

fix 0/0 in ore function field

[mwageringel]

Reviewer: Markus Wageringel

[mwageringel]

comment:2

This looks good to me. You can set this to positive if the bot is happy.

[xcaruso]

comment:3

I think you need to add the trac ticket number in the doctest, e.g. add the sentence:

    We check that :trac:`32109` is fixed::

before the test.

Otherwise, it looks good.

[xcaruso]

Changed reviewer from Markus Wageringel to Markus Wageringel, Xavier Caruso

[kliem]

comment:4

I think this is usually done for bugs that include a discussion, which is not the case here. But sure.