The name ``rollback operator'' has procedural connotations, which in itself is inappropriate (-E8). The name indicates that the operator is computed by moving backwards in time, presumeably from the current transaction time. However, the operator could equally well be computed by a forward motion in time, from the time when the argument relation was created. This makes ``rollforward operator'' an equally acceptable term. Further, the transaction-timeslice operator may be computed using both rollback (decremental computation) and rollforward (incremental computation).
``State query'' seems less precise than transaction-timeslice operator (-E9). It is equally applicable as a name for the valid-timeslice operator (-E8). Further, ``state operator'' is better than ``state query.''
The name ``transaction timeslice'' may be abbreviated to timeslice when the meaning is clear from the context.