theorem levelWelfareLoss_nonneg {W_nn z : ℝ} (hW : 0 < W_nn) (hz : 0 < z) : 0 ≤ levelWelfareLoss W_nn z := mul_nonneg (le_of_lt hW) (welfareDistanceFn_nonneg hz)
thesis/CESProofs/Hierarchy/WelfareDecomposition.lean:177
Theorems 7-8, Propositions 5 and 7, Corollary 3: