Thanks a lot for reporting. This is certainly a bug.
It seems to originate in pari (confirm with qfisom in
https://pari.math.u-bordeaux.fr/dochtml/html/Vectors__matrices__linear_algebra_and_sets.html
)
On Thursday, April 25, 2019 at 11:49:23 AM UTC+2, Ethan Yang wrote:
>
> is_globally_equivalent_to is not symmetric, which it definitely should be
> by virtue of being an equivalence relation. Glancing through the code, this
> seems to be because is_equivalent_to checks whether there is some integral
> transformation from one form to the other, but does not check whether the
> transformation is invertible.
>
> *Steps to reproduce:*
>
> Pick two quadratic forms (many others produce the same bug, but these are
> one example)
> Q = QuadraticForm(ZZ, 2, [2,3,5])
> P = QuadraticForm(ZZ, 2, [8,6,5])
> Q.is_globally_equivalent_to(P) returns True
> P.is_globally_equivalent_to(Q) return False
>
> Version: 8.7
> OS: macOS High Sierra 10.13.6, 64 Bit
>
>
--
You received this message because you are subscribed to the Google Groups
"sage-devel" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to sage-devel+unsubscr...@googlegroups.com.
To post to this group, send email to sage-devel@googlegroups.com.
Visit this group at https://groups.google.com/group/sage-devel.
For more options, visit https://groups.google.com/d/optout.
