<<< native [ EUnderover False (EIdentifier "BASE") (EIdentifier "under script") (EIdentifier "over script") , ESymbol Rel "=" , EUnder False (EOver False (EIdentifier "BASE") (EIdentifier "over script")) (EIdentifier "under script") ] >>> tex \underset{under\ script}{\overset{over\ script}{BASE}} = \underset{under\ script}{\overset{over\ script}{BASE}}