N.Y. Real Property Actions & Proceedings Law § 401: When interests are valued under this article

§ 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.