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.
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