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">BASE</mi> <mi mathvariant="normal">s</mi> <mi mathvariant="normal">t</mi> </munderover> <mo>=</mo> <munderover> <mi mathvariant="normal">BASE</mi> <mrow> <mphantom> <mn>1</mn> </mphantom> <mi mathvariant="normal">s</mi> <mphantom> <mn>1</mn> </mphantom> </mrow> <mrow> <mphantom> <mn>1</mn> </mphantom> <mi mathvariant="normal">t</mi> <mphantom> <mn>1</mn> </mphantom> </mrow> </munderover> </math>
Author: George Chavchanidze, Opera Software ASA