These result illustrate one of the basic principles … set of what we will call base states, … nature of the base state-- it is independent … [footnote: "We do not intend the word "base state" to imply anything more than what is said here. They are not to be thought of as "basic" in any sense. ...]. The base states depend, of course, on the filter used … We must also point out that what we … [where filters are perfect and all other states are ignored].
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