[sage-support] Re: Solve gives incorrect solutions for polynomial

2016-11-09 Thread Simon King
On 2016-11-08, slelievre wrote: > This is a very good question for Ask Sage, would you ask it there? Why should he? He did ask here. And I, for one, dislike the Ask Sage pages to the extent that I wouldn't answer questions there. Cheers, Simon -- You received this message because you are subsc

Re: [sage-support] Question regarding normalization of modular symbols.

2016-11-09 Thread John Cremona
On 9 November 2016 at 00:25, francisco wrote: > Hello, > > I have been computing modular symbols for distinct curves on the Cremona > data base. > But, in a few curves, I recived a WARNING messages like this: > > Warning : Could not normalize the modular symbols, maybe all further > results will b

[sage-support] Re: Solve gives incorrect solutions for polynomial

2016-11-09 Thread Emmanuel Charpentier
A bit of numerical analysis (see enclosed Jupyter notebook) proves that this polynomial has at least two real roots, and quite probably four), one of them being positive. This triggers the question : does Sage have built-in facilities for uncertainty computation ("calcul d'erreurs" in French, b

Re: [sage-support] Re: Unable to launch SageMath 7.4 on macOS Sierra (10.12.1)

2016-11-09 Thread Jeroen Demeyer
On 2016-11-08 23:01, quark67000 wrote: It seems that on 7.4, SageMath has a bad signals.sofile on the Mac version. No, this problem almost certainly has nothing to do with signals.so As Volker said, it is https://trac.sagemath.org/ticket/21772 -- You received this message because you are subs

[sage-support] Re: Solve gives incorrect solutions for polynomial

2016-11-09 Thread kcrisman
> > This is a very good question for Ask Sage, would you ask it there? > > Why should he? He did ask here. And I, for one, dislike the Ask Sage > pages to the extent that I wouldn't answer questions there. > Interesting. If you have ideas on how to improve it so that you might do so, plea

[sage-support] Re: Question regarding normalization of modular symbols.

2016-11-09 Thread chris wuthrich
Most of the normalisation of modular symbols was introduced by me so let me comment. There are currently two ways of computing modular symbols, one using eclib and the other the native sage implementation. Both are only correct up to a scaling factor. That is because their main use was as gene