Fig. 1: The probability ratio index with two parties.
From: On the probability ratio index as a measure of electoral competition

The function B*(x)=4x(1−x) for all (x, 1−x) ∈ Δ(N).
From: On the probability ratio index as a measure of electoral competition
The function B*(x)=4x(1−x) for all (x, 1−x) ∈ Δ(N).