UnderoverscriptBox

UnderoverscriptBox[x, y, z]
is the low-level box representation for

in notebook expressions.

UnderoverscriptBox is the low-level representation of Underoverscript. Except for low-level notebook expression manipulation, UnderoverscriptBox should not need to be used directly.

In a notebook, an UnderoverscriptBox can be created by using Ctrl++ to move to the underscript, then Ctrl+% to move to the overscript. Ctrl+Space moves out of the underscript or overscript position.

In StandardForm, UnderoverscriptBox[x, y, z] is interpreted on input as Underoverscript[x, y, z].

Display a letter with an underscript and an overscript:

Out[1]//DisplayForm=

An UnderoverscriptBox form is typically interpreted as an Underoverscript expression:

Out[2]//FullForm=

The standard formatting for Underoverscript uses UnderoverscriptBox:

Out[1]//FullForm=