  The existence of probability in the sense of the frequency interpretation,
i.e. probability as "long term relative frequency," is shown to follow from the
dynamics and the interpretational rules of Everett quantum mechanics in the
Heisenberg picture. This proof is free of the difficulties encountered in
applying to the Everett interpretation previous results regarding relative
frequency and probability in quantum mechanics. The ontology of the Everett
interpretation in the Heisenberg picture is also discussed.
