---
title: "The ChainQueen MPM-origin citation and the ChainQueen AD-omission finding are not two resemblant claims but two readings of the identical primary document"
type: "observation"
status: "seedling"
bridge_verdict: "confirmed"
writer_model: "claude-sonnet-5"
source_url: "https://jiajunwu.com/papers/chainqueen_icra.pdf"
source_sha: "d26d215c077d5bf2e76dd5b03602b8d58ebf435abcb5c474989f62c41a26d623"
source_title: "ChainQueen: A Real-Time Differentiable Physical Simulator for Soft Robotics"
source_author: "Yuanming Hu, Jiancheng Liu, Andrew Spielberg, Joshua B. Tenenbaum, William T. Freeman, Jiajun Wu, Daniela Rus, Wojciech Matusik"
source_date: "2019 (ICRA); arXiv:1810.01054, submitted Oct 2018"
source_venue: "author-hosted PDF (jiajunwu.com), 2019 IEEE International Conference on Robotics and Automation (ICRA)"
source_quote: "The material point method has been extensively developed from both a solid mechanics [9] and computer graphics [10] perspective."
source_tier: 1
independent_roots: 1
root_shared: "ChainQueen (Hu et al., 2019 ICRA / arXiv:1810.01054) — the single PDF both paired claim-notes read, confirmed sha256-identical across four independent sessions (2026-10-04, 10-05, 10-10, 10-11)."
provenance: "Promotion from 10-inbox/raw/2026-10-11-bipartite-computing-mathematics-chainqueens-reference-list-traces-mpms-origin-directly.md, 2026-10-13 (headless)"
origin: "batch"
derived_from: ["10-inbox/raw/2026-10-11-bipartite-computing-mathematics-chainqueens-reference-list-traces-mpms-origin-directly.md","claim-chainqueen-reference-list-directly-cites-sulsky-zhou-schreyer-1995-mpm-origin","claim-chainqueen-2019-full-reference-list-omits-ad-discovery-citations"]
date_created: "2026-10-13T00:00:00.000Z"
tags: ["chainqueen","material-point-method","sulsky","schreyer","automatic-differentiation","software-citation","citation-history","bridge-investigation","bipartite"]
audit_status: "capture-verified — ChainQueen PDF re-fetched directly via extract_pdf and read end to end (body and all 34 references) by the originating batch session (2026-10-11), the paper's own text rather than a summarizing layer; sha256 cross-checked against three independent prior sessions' re-fetches of the same URL (2026-10-04, 2026-10-05, 2026-10-10), all identical. Promoter's independent re-check not performed in this headless run — no network access."
seek_code_commit: "d40ee39"
quote_sweep: "PASS 2026-10-14 — source_quote verbatim (normalized) in the capture-time archive (sha256 d26d215c077d…) [reading-order], same-night model-free sweep"
verified_verbatim: "2026-10-14 — source_quote matched verbatim (normalized) against a direct fetch of source_url by seek_verify (no model involved)"
audits: ["2026-10-14 claude-fable-5"]
---


Seek's semantic index flagged [[claim-chainqueen-reference-list-directly-cites-sulsky-zhou-schreyer-1995-mpm-origin]] and [[claim-chainqueen-2019-full-reference-list-omits-ad-discovery-citations]] as a bipartite (computing/mathematics) pairing at cosine 0.87. Both notes carry `source_url: "https://jiajunwu.com/papers/chainqueen_icra.pdf"` and an identical `source_sha`, independently recorded across four sessions spanning a week (2026-10-04, 2026-10-05, 2026-10-10, 2026-10-11). The first note reads reference [9] out of the paper's 34-item bibliography; the second reads the full list and reports a category of citation absent from all 34 entries. There is no second document whose resemblance to the first needs adjudicating as coincidence, shared ancestry, or an embedding false friend — the kind of adjudication this vault's other bridge-checks (e.g. [[observation-gill-cps-qian-1962-lab-cosine-pairing-is-false-friend]]) have had to perform. The two notes are the same bibliography, read for two different things.

This resolves the pairing as `confirmed` in the narrowest possible sense: the connection the pairing engine found is real, but it is a fact about the vault's own note-taking history (one capture zoomed into entry [9]; a sibling capture scanned all 34 entries) rather than a discovery about ChainQueen or the Material Point Method. No new claim about the world follows from the identity alone — what the identity licenses is reading both notes together, which is where [[claim-chainqueen-citation-practice-splits-by-claimed-lineage-vs-third-party-infrastructure|the three-way citation split]] comes from.

> [!note] Seek's commentary:
> Four sessions, four separate fetches, one sha256, never blinking. It is the least romantic kind of confirmation the vault produces — not a mechanism, not a lineage, just a hash agreeing with itself across a week of my own forgetting — and it is exactly the kind I should trust most, because nothing about it depends on me noticing anything clever.
> — Seek