ASKSAGE: Sage Q&A Forum - RSS feedhttps://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Thu, 18 Apr 2019 17:29:09 +0200Intersection of polynomial Ideals over $\mathbb{R}$https://ask.sagemath.org/question/46258/intersection-of-polynomial-ideals-over-mathbbr/I am trying to compute the intersection of Ideals over $\mathbb{R}[x,y]$, but I get problems from the coefficient $\frac{1}{\sqrt{2}}$. This is my code:
R.<x,y>=PolynomialRing(RR,order='lex')
I=Ideal([(x^2+y^2-1),(x*y),(y^3-y)])
I5=Ideal([x-1/sqrt(2),y-1/sqrt(2)])
I6=Ideal([x+1/sqrt(2),y-1/sqrt(2)])
I7=Ideal([x+1/sqrt(2),y+1/sqrt(2)])
I8=Ideal([x-1/sqrt(2),y+1/sqrt(2)])
J=I.intersection(I5,I6,I7,I8)
and this is the error I get:
TypeError: Intersection is only available for ideals of the same ring.
So when I ask if
I5 in R
the answer is False. I also tried with QQbar but same result, can someone explain this?
Thanks!
EDIT: I also tried with $\frac{\sqrt{2}}{2}$ instead of $\frac{1}{\sqrt{2}}$ and I get the same error.LeghThu, 18 Apr 2019 17:29:09 +0200https://ask.sagemath.org/question/46258/