<<< mml $$\stackrel{\mathrm{over\; script}}{\mathrm{\_\; baseline\; \_}}=\stackrel{\mathrm{over\; script}}{\underset{\phantom{\mathrm{fail}}}{\mathrm{\_\; baseline\; \_}}}$$ >>> native [ EOver False (EIdentifier "_ baseline _") (EIdentifier "over script") , ESymbol Rel "=" , EOver False (EUnder False (EIdentifier "_ baseline _") (EPhantom (EIdentifier "fail"))) (EIdentifier "over script") ]