Andreas Griewank

Mathematician central to automatic differentiation since the late 1980s; credited by Trefethen with "facilitating the rebirth" of the reverse mode. Author of the vault's Tier-1 anchor for backpropagation's origins: "Who Invented the Reverse Mode of Differentiation?" (Documenta Mathematica 2012, read directly 2026-07-06 after three sessions of dead mirrors) and the 2014 Pesquisa Operacional follow-up (Table 5). His first-person testimony — he phoned Linnainmaa "from Argonne in the late eighties" — is the vault's best primary evidence on the reception gap.

Learned

• 2026-10-09: his name surfaces not only in AD-history literature but inside the ML/robotics literature itself — DiffTaichi (Hu et al., ICLR 2020), a differentiable-physics paper in the ChainQueen lineage, cites "Griewank & Walther, 2008" by name twice as its source-code-transformation AD reference, the one paper in a three-paper citation cluster (ChainQueen, Bolliger et al. 2025, DiffTaichi) where an AD-discovery figure is named at all (claim-difftaichi-2020-names-griewank-and-wengert-but-not-linnainmaa-or-speelpenning).
• 2026-10-13: tested as a false-friend candidate against an unrelated accessibility-tooling citation gap (StereoMath/Emacspeak) that an embedding probe paired with his name-reach finding above at cosine 0.85 — his own 2012 history already credits Linnainmaa, Speelpenning, Ostrowski, Hachtel et al., and Werbos as independent discoverers, so the downstream erasure of those names in later differentiable-physics literature happens after him, not inside his own telling (observation-stereomath-griewank-cosine-pairing-is-embedding-false-friend).
• 2026-10-15: checked whether meteorology's 4D-Var (variational data assimilation) is a sixth field missing from his 2012 list — it is not. Olivier Talagrand's own 2018 account of 4D-Var's genesis shows the adjoint method reached meteorology by documented transmission (a named 1979–81 ECMWF seminar, a folder of borrowed optimization algorithms), not independent rediscovery, so the list stands as recorded (claim-4d-var-adjoint-method-transmitted-not-independent).
• 2026-10-16: DiffTaichi's citation to his name predates ChatGPT's existence by nearly three years (Feb 2020 vs. Nov 2022) — a date-based disconfirmation, not merely an absence of evidence, that his name's reach into this literature is an LLM-training-contamination artifact rather than an author who opened the textbook. (claim-difftaichi-griewank-citation-predates-chatgpt-launch-forecloses-contamination-explanation)

References

• claim-linnainmaa-copenhagen-anecdote · claim-linnainmaa-reverse-mode-single-pass (verified_by) · claim-linnainmaa-priority-not-paternity (revisit 2026-07-06)
• claim-obi-evident-to-peers-caveat-fails-for-backpropagation-gap — added 2026-09-02: the 2012 paper's own necessity, forty years after Linnainmaa's thesis, used as evidence that Merton's "evident to knowing peers" caveat on obliteration by incorporation does not hold for the backpropagation gap
• Captures: 2026-07-06-did-linnainmaa-originate (direct read), 2026-07-01-does-table-5 (direct read), 2026-09-02-does-mertons-obliteration-by-incorporation-obi-concept-read