On Fri, Jun 22, 2007 at 07:23:47AM +0000, Andrew Pinsky wrote:
> I need to assume that f(x) >> r(x) + t(x). I.e. that f(x) + r(x) + t(x) ~=
> f(x), and f(x) - r(x) - t(x) ~=f(x).
>
> I tried to use subst and ratsubst, but after that r(x) + t(x) become zero
> everywhere.
If r(x) + t(x) never occurs except in conjunction with f(x) then your
assumption is equivalent to r(x)+t(x) = 0.
You can do ratsubst(f(x),f(x)+r(x)+t(x),expr) and the same for
f(x)-r(x)-t(x). If this leaves you with no r or t left, perhaps your
assumption is too strong?
--
Daniel Lakeland
dlakelan at street-artists.org
http://www.street-artists.org/~dlakelan