<<< native [ EUnderover False (EIdentifier "- middle -") (EPhantom (EIdentifier "fail")) (EIdentifier "top") , ESymbol Rel "=" , EOver False (EIdentifier "- middle -") (EIdentifier "top") ] >>> tex \underset{\phantom{fail}}{\overset{top}{-\ middle\ -}} = \overset{top}{-\ middle\ -}