If it is to commence upon the full expiration of such precedent estate, it is a remainder and may be transferred by that name. If it is to commence on a contingency which, if it happen, will abridge or determine such precedent estate before its expiration, it shall be known as a conditional limitation.
D.C. Code § 42-511
Proceeding by remainderman to determine whether or not life tenant is still alive, see § 16-1151 et seq. .