The term dynamic is appropriate (as opposed to static) because if the information in the database changes, the partitioning intervals may change. The intervals are determined from intrinsic information.
The existing term for this concept does not have an opposing term suitable to refer to static valid-time partitioning, and can not distinguish between the two types of valid-time partitioning (-E3, +E9). Various temporal query languages have used both dynamic and static valid-time partitioning, but have not always been clear about which type of partitioning they support (+E1). Utilization of these terms will remove this ambiguity from future discussions.