Cfxtrjtrk

Is there any package that fixes the height of tensor indices?

For example, I'd like to horizontally align indices in the following expression representing antisymmetrization of a and b,

documentclass{article}

linespread{1.5}selectfont

begin{document}

$e_i^{[a}q^{b]c}$

end{document}

Is there any universal method not forcing me to use phantom in each expression, like here?

documentclass{article}

linespread{1.5}selectfont

begin{document}

$e_i^{[a}q^{b]c}_{phantom{d}}$

end{document}

You could either put a mathstrut (a box with the height of the ( symbol) into the subscript of q

documentclass{article}

linespread{1.5}selectfont

begin{document}

$e_i^{[a}q_{mathstrut}^{b]c}$

end{document}

or you could adjust the superscript raise and subscript drop document wide

documentclass{article}

linespread{1.5}selectfont

everymath{

    fontdimen14textfont2=1.1ex

    fontdimen17textfont2=0.9ex

}

begin{document}

$e_i^{[a}q^{b]c}$

end{document}

Here's an implementation similar to what the tensor package does, but ensuring empty superscript or subscript is added at each stage.

documentclass{article}

usepackage{amsmath,xparse}



ExplSyntaxOn

NewDocumentCommand{tensor}{mm}

 {

  #1

  group_begin:

  bilbo_tensor:w #2

 }



cs_new_protected:Npn bilbo_tensor:w

 {% start the recursion

  peek_catcode_remove:NTF c_math_subscript_token

   {

    bilbo_tensor_sub:n

   }

   {

    peek_catcode_remove:NTF c_math_superscript_token

     {

      bilbo_tensor_sup:n

     }

     {

      group_end:

     }

   }

 }

cs_new_protected:Nn bilbo_tensor_sub:n

 {% typeset the subscript with a phantom superscript

  {}

  c_math_subscript_token{#1}

  c_math_superscript_token{vphantom{d}}

  % look for a superscript

  bilbo_tensor_sup:w

 }

cs_new_protected:Nn bilbo_tensor_sup:n

 {% typeset the superscript with a phantom subscript

  {}

  c_math_superscript_token{#1}

  c_math_subscript_token{vphantom{d}}

  % look for a subscript

  bilbo_tensor_sup:w

 }

cs_new_protected:Npn bilbo_tensor_sup:w

 {% look for a ^

  peek_catcode_remove:NTF c_math_superscript_token

   {

    bilbo_tensor_sup:n

   }

   {% no ^, end

    group_end:

   }

 }

cs_new_protected:Npn bilbo_tensor_sub:w

 {% look for a _

  peek_catcode_remove:NTF c_math_subscript_token

   {

    bilbo_tensor_sub:n

   }

   {% no _, end

    group_end:

   }

 }



ExplSyntaxOff



begin{document}



$tensor{e}{_i^{[a}}tensor{q}{^{b]c}}$



end{document}