mfenced4

W3C sample	WIRIS
	$\left(a+b\right)$

<math xmlns="http://www.w3.org/1998/Math/MathML">
  <mfenced>
    <mrow>
      <mi>a</mi>
      <mo>+</mo>
      <mi>b</mi>
    </mrow>
  </mfenced>
</math>

Author: Wolfram Research