Good -- then go for it! John
On Wed, Nov 24, 2010 at 1:13 PM, Simon King <simon.k...@uni-jena.de> wrote: > Hi John! > > On 24 Nov., 14:06, John Cremona <john.crem...@gmail.com> wrote: >> This sounds reasonable to me. I know that in general we do not want >> to try to coerce from Z/nZ to GF(n) for prime n since we do not want >> to prove primality except deliberately. The reverse coercion is a >> forgetful functor, so safe. But i nyour example, both GF(p) and Z/pZ >> already exist, in which case it is surely good to coerce from the ring >> to the field. >> >> Of course I may have missed a lot of the point of your suggestion... > > No, that's exactly the point! > > My suggestion is about getting the pushout of the two matrix spaces > right. The pushout is constructed using merging and concatenation > (according to certain rules) of construction functors. > > The construction functors of GF(p) and of Integers(p) *know* whether > they yield a field or not. So, primality is not tested. > > Now, I propose that two QuotientFunctors are merged so that the result > yields a field if and only if one of the given functors yields a > field. > > I just did so, in addition to changing another technical detail. And > this seems to work. > > I guess it will be part of #8800, which is about pushout anyway and > which is where I found the bug. > > Cheers, > Simon > > -- > To post to this group, send an email to sage-devel@googlegroups.com > To unsubscribe from this group, send an email to > sage-devel+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/sage-devel > URL: http://www.sagemath.org > -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
