<<< mml <?xml version="1.0" encoding="UTF-8"?> <math xmlns="http://www.w3.org/1998/Math/MathML"> <mfenced separators="" open="" close=" "> <mi>x</mi> <mi>y</mi> </mfenced> </math> >>> native [ EGrouped [ EIdentifier "x" , EIdentifier "y" ] , EMathOperator "" ]