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Re: Subscript on plus expression

• To: mathgroup at smc.vnet.net
• Subject: [mg128706] Re: Subscript on plus expression
• From: Bill Rowe <readnews at sbcglobal.net>
• Date: Mon, 19 Nov 2012 04:07:57 -0500 (EST)
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• Delivered-to: l-mathgroup@wolfram.com
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On 11/18/12 at 5:15 PM, murray at math.umass.edu (Murray Eisenberg)
wrote:

>On Nov 18, 2012, at 3:57 AM, Dave Snead <dsnead6 at charter.net> wrote:

>>Mathematica fails to parenthesize the a+b in Subscript[Plus[a,b],k]
>>so the output looks identical to Plus[a,Subscript[b,k]]
>>Is this a bug? Is there an option to force the parentheses?

>I don't know off hand of any such option, but is it so unreasonable
>to insert parentheses explicitly in the first? After all, that's
>surely what you'd do if writing it with pencil on paper!

That won't help since Mathematica will evaluate (a+b) to a+b
removing the parentheses before the full expression is
evaluated. The only way I can think of to create something that
at least looks like a subscripted sum would be to enter it in a
manner where Mathematica will not evaluate any part of it.

For example, I could set the input cell format to be a text cell
then create the expression. Of course the end result isn't
something that can be used in other computations.