  A Bell model of the EPR/B experiment also postulates that for each quantum-mechanical state ψ there is a distribution ρ over all the possible pair states λ, which is independent of the settings of the apparatuses. That is, the distribution of the (‘complete’) states λ depends on the (‘incomplete’) state ψ, and this distribution is independent of the particular choice of measurements in the L- and R-wing (including the choice not to measure any quantity). Or formally, for any quantum-mechanical state ψ, L-settings l and l′, and R-settings r and r′: