  Everett's interpretation of quantum mechanics was proposed to avoid problems
inherent in the prevailing interpretational frame. It assumes that quantum
mechanics can be applied to any system and that the state vector always evolves
unitarily. It then claims that whenever an observable is measured, all possible
results of the measurement exist. This assertion of multiplicity has been
understood in many ways by proponents of Everett's theory. Here we shall
illustrate how different views on multiplicity carry onto different views on
spacetime.
