Formatting of right hand side of equation should be identical to formatting of left hand side
<math xmlns="http://www.w3.org/1998/Math/MathML" display="block"> <munderover> <mi mathvariant="normal">B</mi> <mi mathvariant="normal">under</mi> <mi mathvariant="normal">over</mi> </munderover> <mo>=</mo> <mover> <mrow> <munder> <mi mathvariant="normal">B</mi> <mi mathvariant="normal">under</mi> </munder> </mrow> <mi mathvariant="normal">over</mi> </mover> </math>