On Saturday, February 21, 2015 at 12:57:44 PM UTC-8, Simon King wrote: > > > I.e., if P is a commutative additive group, then P.coerce_map_from(ZZ) > should return a morphism in the category of commutative additive groups. > Then, x+0 should work (because the coercion map is a morphism in the > category of additive groups), but x*0 should not work (because it is not > a morphism of multiplicative groups).
I'm not so sure. How does x+3 make unambiguous sense? We can map ZZ onto any cyclic subgroup. There is not necessarily a unique maximal one (for x+0 it obviously doesn't matter which one we choose, though) On the other hand, x*0 should work: A commutative additive group is a left and right ZZ-module, so x*0 and 0*x should match as scalar multiplication. -- 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.
