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Re: Re: More /.{I->-1} craziness

• To: mathgroup at smc.vnet.net
• Subject: [mg106096] Re: [mg106050] Re: More /.{I->-1} craziness
• From: Murray Eisenberg <murray at math.umass.edu>
• Date: Fri, 1 Jan 2010 05:36:00 -0500 (EST)
• Organization: Mathematics & Statistics, Univ. of Mass./Amherst
• References: <hhf5s3$h4o$1@smc.vnet.net> <200912310816.DAA24818@smc.vnet.net>
• Reply-to: murray at math.umass.edu

"One of the first things you learn...."  Hmm... Where exactly in the 
Documentation Center would one be expected to learn about replacement 
rules -- and is that really one of the first things you learn there?

When I ask this, I try to place myself in the position of somebody who 
has NOT come to Mathematica with a long experience of previous versions 
and their associated documentation.

David Bailey wrote:
>
> .... One of the first 
> things you learn about replacement rules is that they operate 
> structurally, and the structure of -I (FullForm[-I]) is Complex[0,-1], 
> which clearly does not match FullForm[I], which is Complex[0,1] - end of 
> story!

-- 
Murray Eisenberg                     murray at math.umass.edu
Mathematics & Statistics Dept.
Lederle Graduate Research Tower      phone 413 549-1020 (H)
University of Massachusetts                413 545-2859 (W)
710 North Pleasant Street            fax   413 545-1801
Amherst, MA 01003-9305