On Saturday, May 9, 2015 at 10:50:08 AM UTC-7, vdelecroix wrote: > > Hi Nils, > > Should I count your e-mail as a -1 for allowing > > PolynomialRing(QQ, (2,3), 'a') > FreeAlgebra(QQ, (2,3), 'a') > > and that I should instead document > > PolynomialRing(QQ, variable_names((2,3), 'a')) > FreeAlgebra(QQ, variable_names((2,3), 'a')) >
Yes. Mathematically, the only thing important for defining a polynomial ring is the dimension (the number of variables). In sage we need variable names in addition, and given a list of variables, it's easy to recover the dimension (from the number of variables specified). By the time we specify the "dimension" as (2,3) I think we're getting into the non-obvious territory. You mean 2*3, but 2+3 (as a 3-variable ring over a 2-variable one, for instance) would be equally plausible. Or it could be a graded polynomial ring in 2 variables with weights 2,3 respectively. The problem you're trying to address is generating variable names according to some pattern. The most direct solution for that is to generate the list of variable names. That already works and works well (using the standard string construction tools in python). Given the problems for dimension specification by anything else than a simple integer, I think we should just rely on the direct solution. -- 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 [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
