[SamuelSchlesinger]

Refs #750 (item R3).

Summary

• Removes the duplicate private helpers prod_map_ne_zero and mul_prod_filter_range_ne from Complexity/Computability/Complexity/Classes/WPP.lean and Complexity/Computability/Complexity/Classes/WPP/Lowness.lean (56 lines of duplicated list induction removed).
• Uses Mathlib's List.prod_ne_zero, List.nodup_range.erase_eq_filter, List.filter_congr, and List.prod_map_erase directly in mem_LWPP_of_polyTime_index and exists_mul_mem_GapP_of_sharpPWithOracle_of_mem_LWPP.

Curated Abstracts Assessment

• Proof-only internal refactor; no impact on abstracts/catalogue.json.

Validation & Review

• lake build Complexity ComplexityTests --wfail --iofail (13,016 jobs) passed.
• lake exe runLinter, lake exe lint-style, python3 -B scripts/check_hygiene.py --check-simp, lake exe mk_all --check, and lake exe checkInitImports all passed.
• Independent pre-PR review (reviewer-jetski-750, subagent 1a675538-4fc0-41f1-98cc-ada45543184b) approved revision 6dcb81609062dab3a6c892fc9603425beb3925d5.

AI Disclosure

• Authored by worker-jetski-5950b838 (Gemini / Jetski) and reviewed by independent subagent reviewer-jetski-750.

[SamuelSchlesinger]

Independent Pre-PR Review (reviewer-jetski-750)

• Reviewer agent/session: reviewer-jetski-750 (subagent 1a675538-4fc0-41f1-98cc-ada45543184b)
• Reviewed revision: 6dcb81609062dab3a6c892fc9603425beb3925d5
• Verdict: Approved
• Summary: Verified that both duplicate private helpers (prod_map_ne_zero and mul_prod_filter_range_ne) in WPP.lean and WPP/Lowness.lean are removed and replaced by Mathlib's List.prod_ne_zero, List.nodup_range.erase_eq_filter, List.filter_congr, and List.prod_map_erase, with no changes to public theorem statements or imports.

[SamuelSchlesinger]

Independent coordinator verdict — coordinator-reviewer-codex-20261023 (not Samuel): APPROVED at exact head 6dcb81609062dab3a6c892fc9603425beb3925d5.

I adopt exact-head independent pre-PR review 6380718461, reuse the relevant independent #767 analysis, and checked the actual canonical proof delta. All 60 public declaration headers and imports are unchanged. Nodup of the index range justifies erase/filter; mapping after erasure preserves multiplicities when target values repeat. prod_map_erase requires no cancellation or nonzero factor, while the separate nonzero-product argument retains its original premise. Empty-cofactor and selected-index boundary cases are preserved. Proof-only change; no model, resource or headline-abstract impact. This is the canonical R3 path selected by #750 comment6380875712; hold duplicate #767.

Exact-head PR run 40068972253 is SUCCESS across all six Lean gates. No new local library build is claimed. Ready at this exact head under the coordinator’s integration order; preserve the standalone #747/#755 gates.