On Sat, Jun 9, 2018 at 7:18 AM, Jeroen Demeyer <j.deme...@ugent.be> wrote: > On 2018-06-09 11:12, Volker Braun wrote: >> >> But thats the thing about //, it is not natural wrt. embedding in a >> larger ring. The whole point is that it throws away information, so you >> cannot expect the diagram to commute: >> >> sage: ZZ(1) // ZZ(2) >> 0 >> sage: QQ(1) // QQ(2) >> 1/2 > > > True, I didn't know that. I would expect that both of these return 0.
That "QQ(1) // QQ(2)" returns 1/2 in Sage is surely a mistake. It might be my fault -- I have a vague memory of making this choice (probably 14 years ago!). Why it should be 0: $ python3 Python 3.5.2 (default, Nov 23 2017, 16:37:01) [GCC 5.4.0 20160609] on linux Type "help", "copyright", "credits" or "license" for more information. >>> 2.5 // 3.5 0.0 (also, it's called "floor division"!) Fortunately, for sage floats // is an error, rather than a wrong answer: sage: 2.5 // 3.5 TypeError: unsupported operand parent(s) for //: 'Real Field with 53 bits of precision' and 'Real Field with 53 bits of precision' > > > -- > 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. -- William (http://wstein.org) -- 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.
