<<< native [ ESubsup (EIdentifier "A") (EIdentifier "B") (EIdentifier "C") , ESymbol Rel "=" , ESubsup (EIdentifier "A") (EIdentifier "B") (EIdentifier "C") , EPhantom (EFraction NormalFrac (EIdentifier "test") (EIdentifier "failed")) ] >>> tex A_{B}^{C} = A_{B}^{C}\phantom{\frac{test}{failed}}