Hi Simon, I can see your reasons. They seem to be from the perspective of someone who knows about computer algebra. But a mathematician and casual user of sage will think of an ideal as a subset of a ring. He/she will be oblivious of the implementation details and expect x in J to be a containment test. Better innocently type x in J and wait a long time (or press ctrl + x) than misinterpreting a result. Experts in computer algebra can still use I.gens(). Else we should rename the class to something like IdealWithGens.
On Sunday, March 10, 2019 at 10:55:17 AM UTC+1, Simon King wrote: > The problem is that ideal containment and equality tests can be very > expensive > (involving Gröbner basis computations), and thus it would be hardly > feasible > to use ideals as, say, keys in dictionaries. Maybe we should better use the generators as keys directly? > If you really > need a mathematically correct containment test and are aware that it may > be expensive, you can explicitly request it. But for many cases, a quick > and dirty mathematically wrong but computationally sound containment > test (or equality test for ideals) suffices. > >From a computer algebra system (written largely by mathematicians) I would expect to do the mathematically correct thing and otherwise warn me that a computational perspective is taken. So +1 for mathematical behavior. Best 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 https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
