Reference · The Applied Higher-Order Functions catalogue
rainbow.algorithms.proofs.ahof.pareto
AHoF multiobjective optimization -- Pareto dominance, the partial order that defines the Pareto front. For a minimization problem with two objectives, a solution a weakly dominates b when a is no worse than b in every objective: dominates? a1 a2 b1 b2 = (a1 <= b1) and (a2 <= b2) expressed as nested if-data over the decidable rational order (no boolean connective needed). Proved native and axiom-free, as worked instances: (2,3) dominates (5,4); the worked certificates 2 <= 5 and 3 <= 4 (native nnrat/at-most); and (6,3) does not dominate (5,4). The soundness of the test for all inputs, and of a Pareto-front filter built on it, is not proved here. Extending to k objectives and extracting the non-dominated front are executable concerns. Requires nnrat/at-most, audit/decide-nnrat-at-most, nnrat/decide-at-most-true-sound, and logic/if-data (all in the D63 checkpoint). Scope (measured by the kernel): this module has 4 worked instances (statements about specific values). None of its theorems is a guarantee about the algorithm for all inputs; `lein verify rainbow.algorithms.proofs.ahof.pareto` prints this classification.
pareto/dominates?
pareto/dominates? : (x₁ x₂ x₃ x₄ : ℚ≥0) → data/Bool
ℚ≥0 = nnrat/NonnegativeRational
pareto/dominates-example
pareto/dominates-example : → pareto/dominates? 2 3 5 4 = data/true
= = equality/Eq
pareto/dominated-in-objective-1
pareto/dominated-in-objective-1 : → 2 ≤ 5
≤ = nnrat/at-most
pareto/dominated-in-objective-2
pareto/dominated-in-objective-2 : → 3 ≤ 4
≤ = nnrat/at-most
pareto/non-dominance-example
pareto/non-dominance-example : → pareto/dominates? 6 3 5 4 = data/false
= = equality/Eq