ReplaceAll / sequential replacements versus joint replacement

*To*: mathgroup at smc.vnet.net*Subject*: [mg55429] ReplaceAll / sequential replacements versus joint replacement*From*: "Ronald Wendner" <Ronald.Wendner at uni-graz.at>*Date*: Wed, 23 Mar 2005 05:34:40 -0500 (EST)*Organization*: Karl-Franzens-Universitaet Graz*Sender*: owner-wri-mathgroup at wolfram.com

Suppose there is an expression e1 which depends, among others, on variables a and b. Replace both a and b by zero: e1/.{a->0,b->0} Mathematica gives, say, result1. Next, consider e2 = e1/.{a->0}; e2/.{b->0} Mathematica gives, say, result2. How can result 1 differ from result 2? For my specific problem, I also attach a short Mathematica notebook. [Contact the author to obtain the notebook - moderator] I'd appreciate any help. Many thanks, Ron

**Follow-Ups**:**Re: ReplaceAll / sequential replacements versus joint replacement***From:*Andrzej Kozlowski <akoz@mimuw.edu.pl>

**Re: ReplaceAll / sequential replacements versus joint replacement***From:*DrBob <drbob@bigfoot.com>