``Transaction-time relation'' is already used by several authors, but other authors use the name ``rollback relation.'' The motive for adopting transaction-time relation is identical for the motive for adopting valid-time relation. The motive for adopting rollback relation is that this type of relation supports a special rollback operation (+E7). But then, by analogy, should not a valid-time relation be named for the special operation on valid-time relations corresponding to the rollback operation, namely transaction timeslice (-E4)?