sqrfree

[Richard B. Kreckel]

On Tue, 1 Aug 2000, Parisse Bernard wrote:
> Doing some tests with square-free factorization, I believe I have
> found a bug.
> Let e by (x+y)^2*(x-y) expanded and call sqrfree(e,x). You do not
> get the original expression, it remains expanded.
> If y is replaced by 1 it seems it works.

Last week I had a look at this.  It was a crude copy of Yun's algorithm
found in Geddes' book.  That algorithm has a minor error, however. :-)
I do think it's fixed in the CVS version now:
> sqrfree(expand((x+y)^2*(x-y)));
(x+y)^2*(x-y)
> sqrfree(expand((x+y)^2*(x-y)),[x]);
(x+y)^2*(x-y)
> sqrfree(expand((x+y)^2*(x-y)),[y]);
(x+y)^2*(x-y)

By the way, I downloaded giac.tgz the day before yesterday and found the
remark "GiNaC import/export is now waiting for a stable interface
format."  What's that about?  Is there anything we can do / clarify?

Regards
    -richy.

PS: You really do have factorization over Z[i]?!?  Are you going to allow
    algrbraic extensions like RootOf and all this?
-- 
Richard Kreckel
<Richard.Kreckel at Uni-Mainz.DE>
<http://wwwthep.physik.uni-mainz.de/~kreckel/>