On Tue, Dec 30, 2014 at 2:47 PM, Nils Bruin <nbr...@sfu.ca> wrote: > On Tuesday, December 30, 2014 1:05:43 PM UTC-8, William wrote: >> >> sage: R.<x> = QQ[] >> sage: S.<y> = QQ[] >> sage: x + y >> [BOOM] -- see [1] > > > Magma does have the capability of having multiple univariate polynomial > rings (and multivariate ones are non-global by default): > >> R<x>:=PolynomialRing(Rationals():Global:=false); >> S<y>:=PolynomialRing(Rationals():Global:=false); >> R; > Univariate Polynomial Ring in x over Rational Field >> S; > Univariate Polynomial Ring in y over Rational Field
Thanks for the clarification. I was unaware of Global:=false for PolynomialRings in Magma. I don't know if that option was there when I learned about Magma's PolynomialRings in the first place (in 1998)... > It's perhaps unfortunate that there is a coercion between them, though: > >> x+y; > 2*x >> y+x; > 2*y Yes, that's unfortunate... > > In any case, the name of the generator is *not* part of the identity of a > parent, whereas in sage it is. Yes, that's really the key distinction. > > -- > 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. -- William Stein Professor of Mathematics University of Washington http://wstein.org -- 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.
