In preparing an example for a course I discovered this seriously misleading feature:
sage: n=(10^19-1)/9 sage: n.factor() 1111111111111111111 sage: n.is_prime() False sage: ZZ(n).is_prime() True What is happening is that when I defined n I used / so that I defined a rational number. And in QQ, there are no primes. sage: n = (10^19-1)//9 sage: n.is_prime() True I don't think there is a good solution for this but surely it will cause confusion (it confused me for at least 5 minutes). John -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support+unsubscr...@googlegroups.com. To post to this group, send email to sage-support@googlegroups.com. Visit this group at http://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/d/optout.
