Werbos's 2006 AD2004 retrospective, read in full, never names LeCun

paul-werbosyann-lecunbackpropagationhistory-of-mlpriority-vs-paternity

Jürgen Schmidhuber's 2014 survey (arXiv:1404.7828) compresses a citation as "Werbos, 1981, 2006." The "2006" half resolves to Paul Werbos's book chapter "Backwards Differentiation in AD and Neural Nets: Past Links and New Opportunities," first presented at the AD2004 conference in Chicago and published in Automatic Differentiation: Applications, Theory, and Implementations (Springer, Lecture Notes in Computational Science and Engineering vol. 50, 2006). Werbos self-hosts the chapter as a preprint at werbos.com; it was fetched directly and read in full — all 15 pages, 773 extracted lines, covering a first-person history of backpropagation's 1960s–1980s development plus a 34-item reference list.

The chapter restates Werbos's own priority narrative:

"Within the ANN field proper, it is generally well-known that backpropagation was first spelled out explicitly (and implemented) in my 1974 Harvard PhD thesis. (For example, the IEEE Neural Network Society cited this in granting me their Pioneer Award in 1994.)"

Across the full text and the reference list, the string "LeCun" does not appear. This directly answers the 2006 half of question-does-werbos-1994-roots-of-backpropagation-or-2006-retrospective-mention-lecun: no. The other half of that question — whether Werbos's 1994 book, The Roots of Backpropagation, mentions LeCun — remains open; no accessible copy of the book was located this session. By contrast, a different, later Werbos primary does name LeCun at length: see claim-werbos-2004-object-nets-patent-names-lecun-against-1994-book.

Limits. This is a claim about citation absence in one specific document, not about influence or priority more broadly. The negative originally rested on a manual full read rather than a mechanical string search (no network tooling is available in promotion sessions); a mechanical count was supplied 2026-10-14 and the negative re-confirmed against a fresh fetch 2026-10-15 — see audit_status. The vault treats this the same way it treats its other Werbos reference-list negatives — see claim-werbos-1988-reference-list-names-no-isaacs-bellman-pontryagin-kelley-or-bryson and claim-werbos-1988-body-pp-350-355-names-no-isaacs-bellman-pontryagin-kelley-or-bryson for the pattern.