Re: Transformation rule problem
- To: mathgroup at smc.vnet.net
- Subject: [mg58046] Re: Transformation rule problem
- From: dh <dh at metrohm.ch>
- Date: Fri, 17 Jun 2005 05:18:44 -0400 (EDT)
- References: <d8rnfg$l4b$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Hi Oliver, I am not sure if I understand your question right. You want to replace ewvery a b by d. But what do you mean by "This replacement is required to work for arbitrary a and b". Well, for the part that I understood: You have 4 different cases: a b, a b^n, a^n b, a^n b^m The rule for the first case is simply: a b -> d second case: a b^n_ -> b^(n-1) d third: a^n b -> a^(n-1) d four: a^n b^m -> a^Max[0, n - m] b^Max[0, m - n] d^Min[m, n] sincerely, Daniel Oliver Buerschaper wrote: > Hi there, > > I'm stuck with a problem concerning transformation rules and was > wondering whether somebody could give me a hint on this. I wouldn't > mind a complete solution either ;-) Here's the problem: > > In a sum like for example > > a^2 b^4 + a^3 b + a^5 + a^5 b > > I'd like to replace every instance of the product (a b) by a different > expression, let's call it d. Thus my result should look like > > d^2 b^2 + a^2 d + a^5 + a^4 d > > This replacement is required to work for arbitrary a and b (especially > when they're functions). I've already tried some simple transformation > rules but they couldn't do the job. > > Cheerio, > Oliver >