This is documentation for Mathematica 7, which was
based on an earlier version of the Wolfram Language.
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UnderscriptBox[x, y]
is the low-level box representation for in notebook expressions.
  • In a notebook, an UnderscriptBox can be created using Ctrl++. Ctrl+Space moves out of the underscript position.
  • The baseline of UnderscriptBox[x, y] is taken to be the baseline of x.
  • UnderscriptBox[x, y] is usually output with y in a smaller font than x.
  • With the option setting LimitsPositioning->True, y is placed in an underscript position when the whole UnderscriptBox is displayed larger, and in a subscript position when it is displayed smaller.
Display a letter with an underscript:
An UnderscriptBox form is typically interpreted as an Underscript expression:
The standard formatting for Underscript uses UnderscriptBox:
The formatted result looks like this:
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