Final Validation Report: Fundamental Limits of Testing IIA

Updated: 2026-09-06

1. Human Verdict

Formalized. The testing lower bound and selected supporting results are proved with the source clarifications in Section 4.

2. Closeout Status

3. Source and Scope

The source is Arjun Seshadri and Johan Ugander, Fundamental Limits of Testing the Independence of Irrelevant Alternatives in Discrete Choice, arXiv:2001.07042v1, 20 January 2020.

The selected results are Theorem 1, Lemmas 2–4, Corollary 1, Appendix Facts 5 and 7, Appendix Lemmas 6, 9–10, and Appendix Corollary 2. Appendix Lemma 8, the standalone arbitrary-graph result attributed to Chu et al., is excluded from this formalization. The selected conclusions instead use the paper’s bipartite cycle-decomposition argument.

4. Researcher Summary of Checked Results

Result Comparison with the paper
Lemma 2 Exact.
Theorem 1 Source clarification: 2 mu(sigma) delta <= 1 keeps the proof’s perturbation in its defined range.
Lemmas 3–4; Appendix Fact 5; Appendix Lemma 6; Appendix Fact 7; Appendix Lemma 9 Exact.
Corollary 1; Appendix Lemma 10 Restricted scope: positive denominator for the rational branch and the valid real-log range.
Appendix Corollary 2 Changed statement: valid range begins at n=3, not n=2.

5. Remaining Boundaries and Gaps

None on the selected surface. Appendix Lemma 8 is excluded as described in Section 3.

6. Additional Assumptions Beyond Paper

None.

7. Proof-Strategy Deviations

Lemma 2 averages test errors over separated components without requiring their mixture to remain separated. See the replacement argument and cancellation example.

The Le Cam coefficient is corrected in Theorem 1’s proof; the theorem’s coefficient is unchanged.

8. Proof Tricks Worth Reusing

9. Generalizations, Conjectures, and Extensions

No additional generalization is established here.

10. Source Clarifications and Exact Readings

The result table links the perturbation range, comparison-incidence denominator, and all-even-subsets endpoint clarifications. The mixture and coefficient proof changes have their main discussion in Section 7.

11. Paper Issues or Caveats

None beyond the domain qualifications in Section 10.

12. Detailed Formalization Evidence

PaperInterface.lean presents 11 selected result claims as transparent targets, and ProofInterface.lean supplies one checked endpoint for each. Source definitions are reviewed at their actual declarations. Appendix Lemma 8 remains a recorded scope exclusion and receives no endpoint or premise credit.

13. Paper Assumption Provenance

Assumptions.lean introduces no paper-local axiom. The 19 paper-local prerequisites and 11 reusable-library prerequisites all match their selected source connections in the paper prerequisite ledger and library ledger. The cited Chu et al. paper supplies context rather than an imported theorem or external proof boundary.

14. Displayed Formula Provenance

The statement map routes the choice-system, IIA, separation-testing, comparison-graph, cycle-decomposition, and balanced perturbation definitions and the selected result formulas. Corrected lower bounds and incidence/decomposition statements are recorded in the source-to-Spec ledger and explained in the source clarification memo.

15. Library Lift Pass

Reusable components include finite distributions and product tests, choice-system distances and IIA projections, graph geodesic trees, bipartite short-cycle extraction, pruning traces, parity accounting, simple-cycle packings, and bounded Eulerian peelings. Paper numbering, the statistical perturbation family, and source-facing theorem bundles remain paper-local.

16. DAG Audit

DependencyDAG.tex places source models and Appendix support before the main results that consume them, separates main-text and Appendix rows, and shows the native Appendix Lemma 9-to-Lemma 10 route. The rendered DependencyDAG.pdf was visually inspected; labels, arrowheads, and the scope-exclusion note are legible, with no clipping or overlap obscuring a dependency edge.

17. Validation Checks

The focused-build receipt records a passing proof-interface build. The import-closure receipt and final closure receipt record the checked Lean closure and terminal obligation graph.

18. Paper Definitions Checked

The checked definitions are the choice-system model, IIA model, separation-testing model, comparison-graph Eulerian model, cycle-decomposition model, and balanced perturbation model. Exact declaration bodies and source routes appear in the statement map and prerequisite ledgers.

19. Named Theorem Statements Checked

Source item Transparent semantic target Checked proof endpoint
Lemma 2 lemma2_testing_reductionSpec lemma2_testing_reduction
Lemma 3 lemma3_chiSquare_mixtureSpec lemma3_chiSquare_mixture
Lemma 4 lemma4_cycle_chiSquareSpec lemma4_cycle_chiSquare
Theorem 1 theorem1_testing_lower_boundSpec theorem1_testing_lower_bound
Corollary 1 corollary1_global_lower_bound_correctedSpec corollary1_global_lower_bound_corrected
Fact 5 fact_convex_hull_denseSpec fact_convex_hull_dense
Lemma 6 lemma_iia_projection_invarianceSpec lemma_iia_projection_invariance
Fact 7 fact_entropy_cross_entropySpec fact_entropy_cross_entropy
Lemma 9 lemma_bipartite_cycle_decompositionSpec lemma_bipartite_cycle_decomposition
Lemma 10 lemma_comparison_incidence_decomposition_correctedSpec lemma_comparison_incidence_decomposition_corrected
Corollary 2 corollary_all_even_subsets_correctedSpec corollary_all_even_subsets_corrected

20. Paper-Facing Statement Validator Ledger

The source-to-Spec ledger contains 11 current judgments: seven matches and four corrected-target matches. The human review packet is the corresponding reader-facing surface.

21. Source-Coverage Audit Ledger

The coverage ledger contains 18 items: 13 covered, four covered as corrected targets, and one scope exclusion for Appendix Lemma 8. The statement map records the source locations and routes for all 18 presentations.