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Separating product terms and keep a custom order in addition

Posted 8 months ago
5 Replies
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I would like to write equations in the form as following: 1/2y + 3/8 x == 2/5 z + w

When this is evaluated it returns enter image description here

however I would like keep the product terms separated from the symbols and the order of addition as placed in the original equation i.e. I would like to keep the following format:

enter image description here

My solution so far is to use this syntax:

HoldForm[HoldForm[1/2]*y + HoldForm[3/8]*x] == 
 HoldForm[HoldForm[2/5] *z + w]

but I am not aware how I can generalize this in a programatic way or if there is any other more simple way to achive the same result.

Any suggestion is welcome.

5 Replies

You can try with a pattern replacement. For example

(1/2 y + 3/8 x == 2/5 z + w) /.
 coeff_?NumberQ*v__Symbol :>
  Inactive[Times][coeff, v]

Thank you for your reply. This really works with the multiplication term, but how can I keep also the order of addition.

I think for the addition order I cannot avoid the hard way:

ClearAttributes[Plus, Orderless] 

while for the product terms:

Replace[expression, Times[x_, y_] -> HoldForm[HoldForm[x]*y], Infinity]

Modifying the function Plus sounds dangerous. I would rather make it Inactive:

(Inactive[Plus][1/2 y, 3/8 x] == Inactive[Plus][2/5 z, w]) /. 
 coeff_?NumberQ*v__Symbol :> Inactive[Times][coeff, v]

Thank you for your comments and help.

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