DETERMINE was one-hop. C answers a member/subset query that holds by SOUND transitive
subsumption when direct entailment misses: member∘subset* and subset∘subset (the
Description-Logic is-a rules). 'Socrates is a man. All men are mortal. Is Socrates
mortal?' -> yes, as told.
wrong=0 hazard surfaced and closed: member∘member is NOT transitive (instance-of vs
subclass-of) — 'Socrates is a man. Man is a species.' does NOT entail 'Socrates is a
species'. That rule is NEVER an edge, so the fallacy is unreachable (bite-tested). The
reader's member/subset split (X is a Y vs all Xs are Ys) is exactly the instance-of/
subclass-of distinction that makes the included rules sound.
Mechanism: SEARCH-then-VERIFY. Reachability over the sound edges finds the chain, then
the proof_chain ROBDD verifies that chain's propositional entailment (O(path) premises).
Full O(n³) grounding into proof_chain was tried and rejected: it overruns the
canonicalizer's per-conjunct recursion, and transitive closure is reachability, not
general SAT. Search-then-verify scales (11-hop chain determines in ~2ms) and keeps the
sound+complete decider as the wrong=0 verifier + proof artifact.
subset is now a supported direct-entailment predicate (a told subset(a,b) answers it);
the other categoricals (disjoint/intersects/some_not) stay excluded. Two existing tests
updated accordingly (subset->ungrounded, disjoint stays unsupported_query).
From the mandated lookback audit: three D0 refusal branches were asserted-but-unproven.
Now they bite:
- not_single_query: reachable from REAL input — a two-question prompt yields two queries.
- malformed_query: a unary `member` query (hand-built; the reader only emits arity-2).
- not_a_comprehension: a non-Comprehension/Refusal input.
No code change — determine.py already refused all three; this closes the
schema-proof-obligation gap (each would now fail if its guard were removed).
The honest gear (roadmap Step 4). `determine(question: Comprehension | Refusal, ctx)`
answers a membership question ("Is X a Y?") ONLY from what the held self has already
REALIZED (R1a structural recall) — never from the field, an LLM, or absence.
Honesty (from the design review): every realizable record is SPECULATIVE, and
ADMISSIBLE_AS_EVIDENCE = {COHERENT}, so a determination grounded in SPECULATIVE records
carries `basis="as_told"` — "based on what I was told (unverified)", NEVER "verified".
Until COHERENT promotion exists (out of scope), D0 produces only as-told assertions or
typed `Undetermined` refusals. No estimation; no corpus mutation (teaching stays HITL
proposal-only).
Soundness (open-world, wrong=0): D0 asserts an answer ONLY on DIRECT structural
entailment by a realized fact; absence never refutes (so it never asserts a positive
answer from missing knowledge — it refuses). It asserts only `answer=True` on a direct
hit; it never asserts False. Negated questions and non-`member` queries are an explicit
`Undetermined` — D0 ships no entailment path the reader cannot exercise.
Tests (test_determine_d0.py, 8) BITE: present-but-non-entailing (a record about the
subject exists but not the asked relation) MUST refuse; the same question against a
fresh context with no realized fact flips Determined→Undetermined (the verdict is
entailment, not mere presence); the negated + unsupported-query refusals are exercised
via hand-built queries (the reader refuses them upstream, so a comprehend-based test
would pass vacuously). Independent of #593: reasons over R0/R1 `member` facts only.
