Discussion


Weak equivalence has been used by Ullman to relate two algebraic expressions (Ullman, Principles of Database Systems, Second Edition, page 309). Hence, ``temporally weakly equal'' is preferable to ``weakly equal'' (+E7).

In comparing ``temporally weakly equal'' with ``snapshot equivalent,'' the former term is longer and more wordy, and is somewhat awkward, in that it contains two adverbs (-E2). ``Temporally weak'' is not intuitive—in what way is it weak? Snapshot equivalent explicitly identifies the source of the equivalence (+E8).