CORE now decides natural-English deductive arguments end-to-end:
'If it rains then the ground is wet. It rains. Therefore the ground
is wet.' -> ENTAILED, rendered over the user's own clauses. Both of
ADR-0256's documented boundary cases (multiword conditional, nested-
negation contraposition) are now decided; their lane gold updated
declined->entailed.
- generate/proof_chain/english.py (new): closed function-word grammar
over OPAQUE clause-atoms (minted ids); if/then, [either] or, and,
three negation forms (leading not / sentential / copular incl.
contractions); typed refusals; honesty caps. Soundness: positive
verdicts are substitution-closed; UNKNOWN is scoped + guarded
(quantifier-led, is-a membership, unnormalizable negation refuse
out of the opaque band).
- render_entailment_english: verdicts quoted back verbatim; UNKNOWN
phrasing explicitly scoped to the opaque reading.
- chat/deduction_surface.py: v2-EN fallback tier AFTER v1/v1b —
monotone widening, byte-identical on previously-served arguments.
- Four en_* shape-bands EARN SERVE via the ADR-0199 arena (720/band,
wrong=0, reliability 0.99087 >= 0.99); 9-band ledger re-sealed.
- evals/deduction_serve/v2_en: 26 hand-authored real-English cases
(content disjoint from the synthetic lexicon), wrong=0; report
re-pinned.
- realizer guard (ADR-0075): deduction surfaces exempt — quoted
templates are not slot-composed articulations (pack 'open'=VERB
was rejecting an honest quoted 'the door is not open'); pinned
cold+warm in e2e.
[Verification]: deductive 84 passed; smoke 180 passed; cognition 122
passed 1 skipped; arena 9x720 wrong=0 all SERVE; lanes v1 28/28,
v2_en 26/26.
core chat now decides Aristotelian syllogisms end-to-end -- the marquee
'basic logical work' widening. Closes Phase 0's fork: the ONLY categorical
decider was evals/syllogism/oracle.py (the sealed independence oracle serving
must not import; INV-25). This ships a production decider.
generate/proof_chain/categorical.py lowers a categorical argument to the
propositional regime (one Boolean atom per term-membership profile) and rides
the already-verified ROBDD engine -- no new decision procedure, soundness
inherits from the flagship. Sound AND complete for the modern/Boolean reading
(Darapti + existential-import-only forms correctly INVALID), with no reliance
on a lucky domain size. Independent of the eval oracle by mechanism (ROBDD-
over-profiles vs brute-force finite-model enumeration); proven by case-for-case
agreement with it across the whole syllogism gold lane.
New: generate/proof_chain/categorical.py, render_syllogism (deterministic
valid/invalid/inconsistent templates), CATEGORICAL shape-band, arena
categorical band (4 valid forms + 2 invalid, by-construction gold cross-checked
vs the independent syllogism oracle), tests/test_categorical_decider.py (8
tests incl. the independence-by-agreement proof).
Changed: chat/deduction_surface.py (categorical branch, license-gated via a
shared _license_gate helper; propositional path byte-identical), arena
DeductionSolver dual-path in lock-step with the composer, re-sealed ledger (5
bands, categorical earns SERVE at 0.99087 wrong=0), Phase-2 lane decide()
mirrors the dual path with the 3 categorical cases reclassified to their true
valid/invalid verdicts + 1 invalid case (n 27->28), report+SHA regenerated.
Honest wrinkles: irregular plurals ('fish') decline with unknown_morphology
(a reader limit, correctly not a wrong); surfaces read in singularized terms
('all whale are animal') -- the exact ids the engine reasoned over, no cosmetic
re-pluralization that could drift from the decision.
[Verification]: smoke 180 passed; cognition 122 passed/1 skipped; core test
--suite deductive 45 passed; test_categorical_decider 8 passed; practice
runner 5 bands all SERVE wrong=0; deduction_serve lane SHA regenerates to the
committed pin.
Wires the verified ROBDD entailment engine (generate/proof_chain,
716/716 wrong=0) into core chat serving. A propositional argument
('P1. P2. ... Therefore C.') is now comprehended, projected, and
decided end-to-end -- the first real working basic-logic workflow:
user question -> CORE decides -> articulated deterministic answer.
New: chat/deduction_surface.py (DEDUCTION composer, sibling to the
existing oov/narrative/example composer pattern), generate/proof_chain/
render.py (deterministic EntailmentTrace -> surface templates, no LLM),
tests/test_deduction_surface.py (15 tests incl. full propositional gold
corpus decided end-to-end across a multi-turn session, wrong=0).
Changed: core/config.py (deduction_serving_enabled flag, default off),
generate/intent.py (IntentTag.DEDUCTION, observability-only -- the core
classify_intent rule table is untouched so flag-off stays byte-identical),
chat/runtime.py (one flag-gated block in the existing pack/teaching/
partial/oov dispatcher).
Design notes (full detail in docs/research/deduction-serve-arc-phase1-
turn-spine-2026-07-23.md): the deduction check runs BEFORE generic intent
classification (never touches classify_intent's rule table) and BEFORE
the empty-vault gate (a live multi-turn probe caught turn-12 silently
falling through once the vault warmed -- pack/teaching/oov are cold-start-
only by design, deduction serving isn't). grounding_source='deduction' is
NOT registered in the closed, Workbench-coupled GroundingSource Literal
(cross-stack TS contract, inert for this arc's core-chat-only consumer,
documented as a deferred follow-up). Band v1 stays propositional-only --
categorical/syllogism arguments commit but honestly decline as
out-of-band; evals.syllogism.oracle is never imported (INV-25 intact).
[Verification]: smoke 180 passed; cognition 122 passed/1 skipped;
test_deduction_surface.py 15 passed; test_dispatch_trace.py +
test_oov_surface.py 26 passed; test_intent*.py 145 passed.
