[sage-support] How can I tell if an algebraic number is rational?

Hi, I need to determine if a given algebraic number is rational. Here is the setup: PolynomialRing(ZZ, 'x') A=-2 B=5 f=x^3 + A*x +B D=-4*A^3-27*B^2 L.c = NumberField(f) Then I need to know if a given number beta=b0+b1*c+b2*c^2 is rational or not. It tried using

Re: [sage-support] How can I tell if an algebraic number is rational?

PolynomialRing(ZZ, 'x') This is only an aside, but I should probably warn that (unlike var, say) this doesn't change x, so it might not do what you're thinking. x is still an Expression, an element of the Symbolic Ring, and so f is also an Expression. You probably want to use something like

[sage-support] Using Sage's python install as the default system python

Is it possible, or advisable, to make the python install included with Sage the default for the entire system on MacOS X? I've tried the Enthought distribution, and it automagically sets itself as the default, but there's a lot of unnecessary duplication if I'm also going to be using Sage. I

Re: [sage-support] How can I tell if an algebraic number is rational?

On Wed, Jun 1, 2011 at 7:30 AM, zsharon zacherysha...@gmail.com wrote: Hi, I need to determine if a given algebraic number is rational.  Here is the setup: PolynomialRing(ZZ, 'x') A=-2 B=5 f=x^3 + A*x +B D=-4*A^3-27*B^2 L.c = NumberField(f) Then I need to know if a given number

[sage-support] Re: How can I tell if an algebraic number is rational?

PolynomialRing(ZZ, 'x') This is only an aside, but I should probably warn that (unlike var, say) this doesn't change x, so it might not do what you're thinking. Thanks. I'm pretty sure that that was mistakenly left over from something I'd tried earlier, but I've taken it out now as it's

[sage-support] Re: How can I tell if an algebraic number is rational?

To test membership, just do     sage: beta in QQ - Robert Wow, thanks. I can't believe I didn't come across that while going over documentation. I guess I just wasn't trying the right search terms. Thanks again, Zach -- To post to this group, send email to sage-support@googlegroups.com

[sage-support] Re: Import Ellipse module?

It turns out I needed to update my version of Sage. I've fixed the problem :) On May 27, 7:59 am, Rajeev Singh rajs2...@gmail.com wrote: On Thu, May 26, 2011 at 10:26 PM, Mel chemmyg...@gmail.com wrote: Do I need to download/load something before I can import the ellipse module? When I

[sage-support] Re: Legend Options in 2D Plots? Title Options in 3D plots?

You're right. I downloaded the most recent version of sage and everything is fine :) On May 25, 10:07 pm, D. S. McNeil dsm...@gmail.com wrote: 1 - On 2D plots, I have been unable to use the legend() attribute and the set_legend_options() attribute. I don't think you have those methods.  I

[sage-support] Re: How can I tell if an algebraic number is rational?

On 6/1/11 11:37 AM, zsharon wrote: To test membership, just do sage: beta in QQ - Robert Wow, thanks. I can't believe I didn't come across that while going over documentation. I guess I just wasn't trying the right search terms. Then again, especially given your other message about

[sage-support] Re: Iterating over finite extension fields.

Hello all, Don't mean to reply to my own question. I guess what I am wondering is why the finite extension of a finite field isn't a finite field. By having the results being a polynomial ring over the prime field it seems as if a lot is lost. Is there room to alter this behavior, or was there a

[sage-support] Re: forming subgroups of the class/unit group of a number field

Sounds like you are doing 2-descent! John Cremona On Jun 1, 1:34 am, zsharon zacherysha...@gmail.com wrote: Hi, I'm trying to form subgroups of the class group and unit group of a number field.  To get the subgroup of squares in C, I start with PolynomialRing(ZZ, 'x') A=-2 B=15 f=x^3 +