Here is another discovery after 15 minutes of debugging: sage: K1 = GF(8,'x') sage: K2 = GF(8,'y') sage: K1(1) == K2(1) False
Nathann On 17 September 2015 at 12:15, Vincent Delecroix <20100.delecr...@gmail.com> wrote: > > > On 17/09/15 06:53, Simon King wrote: >> >> Hi! >> >> On 2015-09-17, Jeroen Demeyer <jdeme...@cage.ugent.be> wrote: >>> >>> On 2015-09-16 16:43, Jean-Pierre Flori wrote: >>>> >>>> Hi, >>>> >>>> I guess one of the issue is that there is no canonical map between two >>>> different representations of the same finite field (so no coercion). >>> >>> >>> The question is really: is the map between representations of the same >>> finite field, which differ only in variable name, "canonical"? >> >> >> I think that it is in the same way canonical as we have a >> name-preserving map between polynomial rings. >> >> The real problem here is that *conversion* gives rise to an error >> that mentions *coercion*. >> >> sage: K.<x> = GF(25) >> sage: L.<y> = GF(25) >> sage: K(y) >> Traceback (most recent call last): >> ... >> TypeError: unable to coerce from a finite field other than the prime >> subfield >> >> That's clearly a bug. Conversion should work, even if it isn't canonical >> and thus doesn't qualify as coercion! >> >> Is there no ticket for it already? I think I have seen that issue >> before. > > > +1 > > The behavior should be similar to > > sage: Rx.<x> = ZZ[] > sage: Ry.<y> = ZZ[] > sage: Rx(3*y**2 + 1) > 3*x^2 + 1 > sage: x+y > Traceback (most recent call last): > ... > TypeError: unsupported operand parent(s) for '+': 'Univariate Polynomial > Ring in x over Integer Ring' and 'Univariate Polynomial Ring in y over > Integer Ring' > > Vincent > > > -- > You received this message because you are subscribed to a topic in the > Google Groups "sage-devel" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/sage-devel/1rIMPfChUM4/unsubscribe. > To unsubscribe from this group and all its topics, 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 http://groups.google.com/group/sage-devel. > For more options, visit https://groups.google.com/d/optout. -- 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 http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
