Final answer:
The question relates to the concept of view equivalence in transaction scheduling in a database system, where schedules must satisfy certain conditions including that the 'last' write operation in one schedule corresponds to the 'last' write operation in the other.
Step-by-step explanation:
The question is about the concept of view equivalence in database systems, specifically in the context of transaction scheduling. Two schedules are said to be view equivalent if they meet certain conditions regarding how transactions write to data items.
The missing word in the sentence "If the operation Wk(Y) of Tk is the last operation to write item Y in S, then Wk(Y) of Tk must also be the last operation to write item Y in S'." is the word last. This criterion ensures that the final state of the database with respect to the value of item Y is the same in both schedules. It's imperative that the same transactional operation is the final one affecting the item's value for the schedules to be considered view equivalent.
Implicit in this concept is the assumption that the timing of operations, as perceived by observers or processes in both schedules S and S', is consistent. This is crucial for maintaining database consistency and ensuring that concurrent transactions do not lead to conflicting data states.