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Re: subscripted local variables?

• To: mathgroup at smc.vnet.net
• Subject: [mg80726] Re: subscripted local variables?
• From: "Kevin J. McCann" <Kevin.McCann at umbc.edu>
• Date: Thu, 30 Aug 2007 02:33:56 -0400 (EDT)
• Organization: University of Maryland, Baltimore County
• References: <fath6p$3o7$1@smc.vnet.net>

I disagree with the previous comments on the use of subscripted symbols. 
I do it all the time. Here is what I suggest:

Use the Notation package. Here is an example. You should note that in 
this example "xsub2" is turned into a symbol. This means that Mathematica puts a 
wrapper around it so that it treats "xsub2" as a symbol. Drop the stuff 
below into a new notebook, highlight the whole thing and do a 
Cntrl-Shift-N to see the notation, then execute.

Kevin


(*Here is a simple subscript, which works ok unless x is defined:*)

Subscript[x, 2]


FullForm[Subscript[x, 2]]


x = 3;

Subscript[x, 2]


(*Ooops! Now undefine x:*)

x =.

(*and load the Notation package*)

<< Notation`

(*Use the Symbolize button from the Notation Palette:*)

Symbolize[\!\(\*
TagBox[
SubscriptBox["x", "2"],
"NotationTemplateTag"]\)]

(*Now, note that the FullForm has changed:*)

FullForm[Subscript[x, 2]]


(*Mathematica has put a sort of wrapper around the whole thing so \
that it is treated as a single entity. Now let's define x again:*)

x = 3;

(*This time, however, everything works:*)

Subscript[x, 2]