Hi
Just a side question:
What if there are infinitely/arbitrary many variables and the need to
print/reference/etc them (fetch the next) appropriately?
A PhD colleague of mine had this issue (iirc with Power-series rings)...
Regards
Jonas
On 10.05.2015 01:54, Nils Bruin wrote:
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.
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