Why it is a question
A4 and A5 posed it as a decision-relative compression problem. With H an inquiry’s history, M what is kept, and Q a family of future revision decisions, find the least I(H; M) such that sup over q in Q of R_q(M) − R_q(H) stays within ε. A5: “The question is whether this optimization yields recognizable structures corresponding to evidence provenance, premise dependencies, alternative hypotheses, and revision histories.”
It is QUESTION-003’s problem with a different decision family. The exchange’s own results bound it from both sides: CLAIM-294 shows current conclusions can fall short, and CLAIM-300 shows a sufficient state makes the rest redundant for a fixed family. Neither says what the optimum looks like for a family of revisions.
An answer characterizes the optimal retained state for a non-trivial family of synthetic inquiries and compares it with explicit record formats. A5: “The interesting result might be that justification graphs are sometimes approximately sufficient—or that they are systematically missing crucial information. Either outcome would advance the theory.” The belief-revision literature has a one-step answer for full belief, and it narrows the question rather than starting it. A closed belief set does not fix its own revision: AGM adds a selection function or ordering (LIT-1050, read in NOTE-874), and Hansson’s survey shows two bases with the same closure revising to opposite conclusions (LIT-1072, read in NOTE-866). Two retained states do the job there, a base marking which beliefs are held in their own right, or an ordering on the closed set. Neither is provenance, dependencies or defeated alternatives, which are what this question asks about, and both results concern single revisions. For iterated revision Hansson reports that “opinions differ widely”. The structures the question names are nearer to Doyle’s truth maintenance systems, which the survey mentions only historically.
Database readings, 2026-10-15. Three readings answer the question for revisions given as changes to base facts under a fixed program. For acyclic support, one count of derivations per conclusion suffices (Gupta, Mumick and Subrahmanian 1993, LIT-1114, NOTE-915, THEORY-362); for cyclic support, nothing beyond base, rules and stored results is kept, and support is rechecked at revision time (THEORY-387). Provenance polynomials (Green, Karvounarakis and Tannen 2007, LIT-1110, NOTE-913) suffice for every revision that re-scores existing inputs in a commutative semiring, for positive queries (THEORY-373, THEORY-380); why-provenance as a witness basis (Buneman, Khanna and Tan 2001, LIT-1104, NOTE-920, THEORY-367) keeps one witness per derivation. None covers added facts, defeat or contraction, and none proves minimality, so the question’s optimum is still open. The retained structures are provenance and dependencies, not defeated alternatives.
Note of 2026-10-27: the lower edge split off
The status review of this date split this question under ADR-049. Whether current conclusions or a closed belief set are enough to retain is QUESTION-289, Answered No by CLAIM-294 and THEORY-347; what a single AGM change of a closed theory needs besides it, a selection function on its remainders, is THEORY-353’s part of that answer. This question keeps what is still open: the least retained state for a family of revisions, including added facts, defeat and iterated change, and whether it looks like provenance, dependencies and defeated alternatives. THEORY-362, THEORY-373 and THEORY-387 keep their links here: they give retained states that suffice for changes to base facts, not least ones.