Partition tree x∈{0,1}” Index(x,i)=xi ie[n] Alice Px Bob ·p=∑Pxx 。In general: 0 0 0 0 -Distri.p on (0,1n 0 1 -Partition tree for {o,1n 0 1 0 1 -Gain H(6)-H(E)at v 1 0 1 0 ·v is partitioned by(δ，1-o) 1 1 1 1Partition tree • ρ = ∑x px ∙ρx • In general: – Distri. p on {0,1}n – Partition tree for {0,1}n – Gain H(δ)-H(ε) at v • v is partitioned by (δ,1-δ) Alice Bob x{0,1}n i[n] Index(x,i) = xi ρx 0 0 0 0 0 1 1 1 1 0 0 1 1 1 0 0 1 1