Research · v0.4 · Jul 2026
Formal specification of the Ackren engine
The complete mathematical description of the engine, in 118 pages, with a third of it given to failure.
Download
The paper, as published
WP-2026-01, Ackren: a deterministic conversational engine with per-response derivability, version 1.5, 18 pages, CC BY 4.0. The paper is this specification compressed to publication length; measured figures cite the engine report for build df353a9add9aa347, and superseded figures are struck in place, never deleted.
Contents
What the document covers
The specification describes the engine as a composition of eight stages, each of which returns either a result or a typed flag. It fixes the algebra those flags live in, proves that flags outrank results at selection, and states the exact conditions under which a bridging inference may be written into the derivation record.
Roughly forty pages are the failure accounting: eleven rows, each with its detection condition and its soundness status. Two of those rows are unsound and are marked as such in the document rather than in an erratum.
How to read it
Start at the back
A technical evaluator at a regulated buyer should read the failure accounting first. It is the part that determines whether this architecture can meet a traceability obligation, and it is the part we would most like to be argued with.
The document is dated, versioned and citable. Corrections appear in the development log as dated entries with the superseded text struck, so a reader who cites v0.4 can find out what changed after them.
A specification is not an engine
This describes a system whose working demo is four to six months out. Read it as a design that can be checked, not as evidence that the design has been built.