<<< native [ ESuper (ENumber "2") (ESuper (ENumber "3") (ENumber "4")) , ESymbol Rel "=" , ESuper (ENumber "2") (ESuper (ENumber "3") (EOver False (ENumber "4") (EPhantom (ENumber "5")))) ] >>> mml $$2^{3^4}=2^{3^{\stackrel{\phantom{5}}{4}}}$$