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Re: Readability confuses mathematica?

• To: mathgroup at smc.vnet.net
• Subject: [mg44533] Re: Readability confuses mathematica?
• From: Oliver Friedrich <oliver.friedrich at tzm.de>
• Date: Thu, 13 Nov 2003 05:57:51 -0500 (EST)
• Organization: TZ Mikroelektronik
• References: <botcm2$ci7$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

patrick.m.lahey at aero.org (patrick_m_lahey) wrote in news:botcm2$ci7$1
@smc.vnet.net:

> I am new to mathematica so perhaps there is a simple answer to this
> 
> Consider:
> 
> In[1]:= D[x-x0,x]
> 
> except that x0 is really x ctrl-- 0 (x subscript 0).  Normally that
> would be a completely independent variable from x but not according to
> mathematica!
> 
> Out[1]=1-Subscript(1,0)[x,0]
> 
> (the (1,0) is a superscript of Subscript).
> 
> One of the things that attracted me to mathematica was the ability to
> work with expressions that closely mirrored the true expressions of
> interest (a readability issue really...).
> 
> Is there anything that can be done here?
> 
> 

Hallo Patrick,

are you using at least Mathematica 4? Then try to use the Notation 
package.
The problem is that Mathematica treats expressions like x Subscript 0 not 
as a symbol but as a coumpound expression and thus tries to derive the 
function Subscript.
The Notation package provides a method called "Symbolize" where you can 
kind of transform Compound expressens into real symbols. It seems to add 
rules to interpreting input and formatting output. So Subscript[x,0] is 
transformed to a symbol called x_Subscript_0. This is treat like a real 
symbol. On output it is formatted in a appropriate way.
But I've found that these function don't work correctly when you want to 
put out symbolized expressions in TraditionalForm. Maybe anyone out there 
who knows an answer to this issue.

Regards
Oliver Friedrich