Methods and apparatus, including computer program products, for defining rights applicable to a digital object. A set of initial rights and a set of modifying rights are received for the digital object. At least one of the set of initial rights and the set of modifying rights specifies one or more conditions on rights in the respective set of rights. A new set of rights is defined for the digital object based on the set of initial rights and the set of modifying rights. The new set of rights specifies one or more new conditions on rights in the new set of rights. The new conditions are defined based on one or more of the conditions in the set of initial rights and/or the set of modifying rights.