Hi Eric, On 2014-06-02, Eric Gourgoulhon <egourgoul...@gmail.com> wrote: > In this frame, there should be two distinct zero elements, namely A.zero()= >=20 > and B.zero(), i.e. we should have > A.zero() =3D=3D B.zero() > but > A.zero() is B.zero() > should return False. Correct ?
If you rely on the default mechanisms and establish a coercion from B to A, then A.zero() == B.zero() is equivalent to A.zero() == A(B.zero()) Presumably A(B.zero()) will return A.zero(). Hence, probably you do not need to do anything special to establish equality of A.zero() and B.zero(). Probably it would be possible to implement the sub-structur B of A with "facade parents". See, for example, Primes.__init__. This means that the the elements of B are actually elements of A, i.e. sage: B.zero().parent() is A True sage: B.zero() is A.zero() True However, if you decide that B has features that are sufficiently different from A, you can implement a "usual" parent-element relation, hence sage: B.zero().parent() is A False sage: B.zero().parent() is B True sage: B.zero() is A.zero() False Cheers, Simon -- 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.
