<<< native
[ ESubsup (EIdentifier "V") (EIdentifier "m") (EIdentifier "n")
, ESymbol Rel "="
, EUnderover
    False
    (ESubsup (EIdentifier "V") (EIdentifier "m") (EIdentifier "n"))
    (EPhantom (EText TextNormal "d"))
    (EPhantom (EText TextNormal "d"))
]
>>> tex
V_{m}^{n} = \underset{\phantom{\text{d}}}{\overset{\phantom{\text{d}}}{V_{m}^{n}}}