Both ``snapshot equivalent'' and ``weakly equivalent'' have strong support by members of the temporal database community, and it has not been possible to reach a consensus on which of these two names is preferable; we have therefore adopted both names, listed in alphabetical order, for this concept.
``Weak equivalence'' was originally used by Ullman to relate two algebraic expressions (Ullman, Principles of Database Systems, Second Edition, page 309). We rely on the context to disambiguate this usage from the usage specific to temporal databases.
``Snapshot equivalent'' explicitly identifies the source of the equivalence (+E8).