Re: Adding new rules to Simplify

*To*: mathgroup at smc.vnet.net*Subject*: [mg56341] Re: Adding new rules to Simplify*From*: John Billingham <John.Billingham at Nottingham.ac.uk>*Date*: Fri, 22 Apr 2005 06:23:30 -0400 (EDT)*References*: <27457333.1114080708731.JavaMail.jakarta@nitrogen.mathforum.org>*Sender*: owner-wri-mathgroup at wolfram.com

Here's another one! r1[x_ /; ! FreeQ[x, f]] := x /. f[y_] -> a[y]/b[y]; r1[x_] := x; r2[x_ /; ! FreeQ[x, g]] := x /. g[y_] -> b[y]/a[y]; r2[x_] := x; Simplify[f[X] g[X], TransformationFunctions -> {r1, r2}] gives f(X) g(X) I would have hoped to get 1 here, particularly since r1[r2[f[X]g[X]]] gives me 1 as expected! So I tell it to Simplify using just two rules, the successive application of which gives 1, but Mathematica fails to simplify at all. What's going on here?? John

**Follow-Ups**:**Re: Re: Adding new rules to Simplify***From:*Andrzej Kozlowski <akoz@mimuw.edu.pl>