N.Y. RPP. LAW § 339-i : NY Code - Section 339-I: Common elements

1. Each unit shall have appurtenant thereto
  a common interest as expressed in the declaration. Such  interest  shall
  be  (i) in the approximate proportion that the fair value of the unit at
  the date of the declaration bears to the then aggregate  fair  value  of
  all  the units or (ii) in the approximate proportion that the floor area
  of the unit at the date of the declaration bears to the  then  aggregate
  floor  area  of  all  the  units,  but such proportion shall reflect the
  substantially exclusive advantages enjoyed by one or more  but  not  all
  units in a part or parts of the common elements or (iii) the interest of
  each of the units shall be in equal percentages, one for each unit as of
  the  date  of  filing  the  declaration,  or in equal percentages within
  separate  classifications  of  units  as  of  the  date  of  filing  the
  declaration,  or  (iv) upon floor space, subject to the location of such
  space and the additional factors of relative value to other space in the
  condominium, the uniqueness of the  unit,  the  availability  of  common
  elements  for exclusive or shared use, and the overall dimensions of the
  particular unit.
    2. The common interest appurtenant to each unit as  expressed  in  the
  declaration  shall  have  a permanent character and shall not be altered
  without the consent of all unit owners affected, expressed in an amended
  declaration. However, the declaration may contain provisions relating to
  the appropriation,  taking  or  condemnation  by  eminent  domain  by  a
  federal,   state   or  local  government,  or  instrumentality  thereof,
  including, but not limited to, reapportionment or other  change  of  the
  common  interest appurtenant to each unit, or portion thereof, remaining
  after a  partial  appropriation,  taking  or  condemnation.  The  common
  interest  shall  not  be separated from the unit to which it appertains.
  Nothing contained in this article shall prohibit  the  division  of  any
  unit  and  common interest appurtenant thereto in a non-residential unit
  in the manner permitted by the declaration and bylaws, including changes
  in the number of rooms; in no case may such division result in a greater
  percentage of common interest for  the  total  of  the  new  units  than
  existed  for  the original unit before division. Where authorized by the
  declaration and bylaws, an appropriate amendment to the declaration  may
  be  filed  by  the  new unit owners under the same file number and under
  procedure set forth in section three hundred thirty-nine-p  hereof,  and
  the  local  tax  authorities shall provide and certify upon the proposed
  amendment a conforming tax lot number upon completion of the new units.
    3. The common elements shall remain undivided and no right shall exist
  to partition or divide any thereof, except as otherwise provided in this
  article. Any provision to the contrary shall be null and void.   Nothing
  in  this  subdivision  shall be deemed to prevent ownership of a unit by
  the entireties, jointly or in common.
    4. Each unit owner may use the common elements in accordance with  the
  purpose  for  which they are intended, without hindering the exercise of
  or encroaching upon the rights  of  the  other  unit  owners,  but  this
  subsection  shall  not  be  deemed  to  prevent  some unit or units from
  enjoying substantially exclusive advantages in a part or  parts  of  the
  common elements as expressed in the declaration or by-laws.
    5.  The  unit owners shall have the irrevocable right, to be exercised
  by the board of managers, to have access to each unit from time to  time
  during reasonable hours to the extent necessary for the operation of the
  property,  or  for making emergency repairs therein necessary to prevent
  damage to the common elements or to  another  unit  or  units,  and  the
  by-laws   may   contain   reasonable   rules  and  regulations  for  the
  administration of this provision as the privacy of  the  units  and  the
  protection  of  them  and their contents from burglary, theft or larceny
  requires.