⁴The justification of the terms (y₁ −1) and (y_i+1) is as follows. Recall that (y₁,…,y_C) ∈ 𝕐 = {1,2}×{−1,0,1}^C−1. Thus, y₁ ∈{1,…,3^Q+2} implies that (y₁ − 1) ∈{0,1,…,3^Q+2 − 1}, while y_i ∈{−1,0,1} implies that (y_i + 1) ∈{0,1,2}.