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"> <mover> <mi mathvariant="normal">B</mi> <mi mathvariant="normal">long over script</mi> </mover> <mo>=</mo> <mover> <mrow> <mi mathvariant="normal">B</mi> </mrow> <mrow> <mi mathvariant="normal">long over script</mi> </mrow> </mover> </math>
Author: George Chavchanidze, Opera Software ASA