  The Everett-interpretation description of isolated measurements, i.e.,
measurements involving interaction between a measuring apparatus and a measured
system but not interaction with the environment, is shown to be unambiguous,
claims in the literature to the contrary notwithstanding. The appearance of
ambiguity in such measurements is engendered by the fact that, in the
Schroedinger picture, information on splitting into Everett copies must be
inferred from the history of the combined system. In the Heisenberg picture
this information is contained in mathematical quantities associated with a
single time.
