<math display="block"> <mml:mrow> <mml:mover> <mml:mrow> <mml:mover> <mml:mi>U</m:mi> <mml:mo>=</m:mo> </m:mover> </m:mrow> <mml:mrow></m:mrow> </m:mover> <mml:mo stretchy='false'>(</m:mo><mml:mi>&#x03B7;</m:mi><mml:mo>;</m:mo><mml:mi>&#x03C9;</m:mi><mml:mo stretchy='false'>)</m:mo><mml:mo>=</m:mo><mml:msub> <mml:mi>E</m:mi> <mml:mi>A</m:mi> </m:msub> <mml:mo stretchy='false'>[</m:mo><mml:mover> <mml:mi>U</m:mi> <mml:mo>&#x223C;</m:mo> </m:mover> <mml:mo stretchy='false'>(</m:mo><mml:mi>&#x03B7;</m:mi><mml:mo stretchy='false'>)</m:mo><mml:mo>;</m:mo><mml:mi>&#x03C9;</m:mi><mml:mo stretchy='false'>]</m:mo> </m:mrow> </m:math>