§ 401. When interests are valued under this article. The following
interests shall be valued in the manner provided by this article: (a) an
interest in real property dependent as to value upon the duration of one
or more lives in being, whether such interest is present or future; and
(b) a future interest preceded only by one or more interests described
in clause (a); whenever 1. the owner of such interest is entitled to
receive a sum in gross in satisfaction of, or in compensation for
impairment of, his interest in real property which has been transformed
into a fund by judicial action or proceeding; or 2. ownership of real
property is divided into successive legal interests, including one or
more interests dependent as to value upon the duration of one or more
lives of persons in being, and the fraction of complete ownership
belonging to each partial owner must be ascertained so as to permit an
adjudication of the fraction of some new capital expenditure required
either for the payment of a mortgage, special assessment or other lien
upon such property, or for the satisfaction of an obligation imposed by
law as an incident of ownership; or 3. such valuation is necessary for
the final determination of some action or proceeding, other than an
action or proceeding for which the insurance law, the workmen's
compensation law or the tax law prescribes methods of valuation.