[GiNaC-list] bug with is_polynomial?

[Alexei Sheplyakov]

Hello!

On Tue, Aug 05, 2008 at 01:58:59PM -0700, Jonathan Cross wrote:

> When there is an expression involving a non-integer power---even when
> the expression is independent of the dummy variable of the polynomial---
> then the expression is not considered a polynomial by GiNaC.

Mathematically such an expression is not a polynomial (over field of
rational numbers). See you favourite book on the (commutative) ring
theory for more details.

>    // here are two expressions that are both polynomials with respect to s.
>    GiNaC::ex    expr1 = sin(x) + 2*s;
>    GiNaC::ex    expr2 = pow(2,x) + 2*s;

I don't quite understand why these expressions are polynomials. Could
you elaborate, please?


Best regards,
	Alexei

-- 
All science is either physics or stamp collecting.

-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 827 bytes
Desc: Digital signature
Url : http://www.cebix.net/pipermail/ginac-list/attachments/20080806/19648516/attachment.sig