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> <mrow> <munderover> <mi mathvariant="normal">BASE</mi> <mi mathvariant="normal">first under script</mi> <mi mathvariant="normal">second overscript</mi> </munderover> </mrow> <mi mathvariant="normal">second one</mi> <mi mathvariant="normal">first overscript</mi> </munderover> <mo>=</mo> <munderover> <mrow> <mover> <mrow> <munder> <mi mathvariant="normal">BASE</mi> <mi mathvariant="normal">first under script</mi> </munder> </mrow> <mi mathvariant="normal">second overscript</mi> </mover> </mrow> <mi mathvariant="normal">second one</mi> <mi mathvariant="normal">first overscript</mi> </munderover> </math>