This is documentation for Mathematica 3, which was
based on an earlier version of the Wolfram Language.
 1.10.6 Subscripts, Bars and Other Modifiers Here is a typical palette of modifiers. Mathematica allows you to use any expression as a subscript. In[1]:= Out[1]= Unless you specifically tell it otherwise, Mathematica will interpret a superscript as a power. In[2]:= Out[2]= Special input forms based on control characters. The second forms given should work on any keyboard. This enters a subscript using control keys. In[3]:= Expand[(1 + x_1+n)^4] Out[3]= Just as ^ and _ go to superscript and subscript positions, so also & and = can be used to go to positions directly above and below. With the layout of a standard English-language keyboard & is directly to the right of ^ while = is directly to the right of _. Ways to enter some common modifiers using control keys. Here is . In[4]:= x &_ Out[4]= You can use as a variable. In[5]:= Solve[a^2 == %, a] Out[5]= Ways to enter modifiers without control keys. All these forms can be used only inside \!\( ... \ ).