L.6.1.4 Box Object

The Box object is used to group components of an expression or equation (such as the multiple characters of a compound operator), to apply a single property to everything in the box. The Box serves a number of distinct purposes, including grouping characters to form a single operator (an operator emulator), and thereby inheriting the alignment and manual break properties of operators; grouping a

differential such as 𝑑𝑥 a different script level.

; preventing line breaks from occurring within; and allowing text inside to have

An example of a Box serving as an operator emulator is:

Example:

Example XML:

<m:oMathPara>
  <m:oMath>
    <m:r>
      <m:t>a</m:t>
    </m:r>
    <m:box>
      <m:boxPr>
        <m:opEmu m:val="on" />
      </m:boxPr>
      <m:e>
        <m:r>
          <m:t>==</m:t>
        </m:r>
      </m:e>
    </m:box>
    <m:r>
      <m:t>b</m:t>
    </m:r>
  </m:oMath>
</m:oMathPara>