<<< mml $$T_m^n=\stackrel{\phantom{\text{x}}}{T_m^n}$$ >>> native [ ESubsup (EIdentifier "T") (EIdentifier "m") (EIdentifier "n") , ESymbol Rel "=" , EOver False (ESubsup (EIdentifier "T") (EIdentifier "m") (EIdentifier "n")) (EPhantom (EText TextNormal "x")) ]