[PURRS-devel] [Fwd: Problem with subs]

[Tatiana Zolo]

-------- Original Message --------
Subject: Problem with subs
Date: Thu, 28 Feb 2002 11:43:51 +0100
From: Tatiana Zolo <zolo at cs.unipr.it>
Reply-To: ginac-list at zino.physik.uni-mainz.de
To: "ginac-list at zino.physik.uni-mainz.de"
<ginac-list at zino.physik.uni-mainz.de>
CC: Alessandro Zaccagnini <zaccagni at prmat.math.unipr.it>

We do not understand how subs works in some cases: we tried the
following
ginsh session

> p=x+1;
1+x
> subs(p,x==k-1);
k
> subs(p,x==x-1);
-1+x
> subs(p,x==x-2);
-1+x
> subs(p,x==x^2-1);
x^2
> subs(p,x==x^2);
1+x^2

so, apparently, subs is sometimes wrong. We couldn't find anything in
the
documentation to explain this fact.


Thank you very much. Best wishes


Alessandro Zaccagnini
Tatiana Zolo

purrs developers,
at the University of Parma, Italy