> 2) to evaluate "a in B": if A is the parent of a, and P is the push-out of > A and B, then "a in B" yields True if and only if the following hold: > -- a can be converted into an element of B, say b = B(a); > -- the images of a, b in P are equal *and* B maps injectively into P > (similar to rule 1 above, but asymmetric w.r.t. A, B). >
Somewhat coincidentally, this algorithm also makes "Infinity in RR" evaluate to False: in this situation a = Infinity, A = InfinityRing, B = RR, P = InfinityRing, and the coercion map B -> P is not injective, so the result is False. On the other hand, applying rule 1 to RR(Infinity) == Infinity still yields True. The coercion map RR -> InfinityRing does not currently know that it is not injective, but this should be easy to fix. Peter -- 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/groups/opt_out.
