A Note on the Characterization of Fisher’s “Ideal Index”
Helmut Funke, Joachim Voeller · 1978
If the deduction of a certain index from a set of given conditions is stated in the form of an “if and only if theorem”, then we speak of a characterization of the particular index. That is, the index in question not only satisfies the required conditions but also represents the only index which can be deduced from these conditions.