The first SIZEABLE, honestly-verified reasoning capability — built on CORE's
own terrain (exact, verifiable, deterministic), not GSM8K's stochastic terrain.
THE OPERATOR (generate/proof_chain/entail.py, ADR-0206):
- evaluate_entailment(premises, query) -> entailed | refuted | unknown | refused.
- The multi-hop inference operator evals/symbolic_logic/gaps.md said did not exist
("no operator that takes A->B, B->C and returns A->C") and ADR-0205 deferred.
- Built on the ADR-0201 ROBDD canonicalizer: premises |= Q iff (AND P) -> Q is a
tautology. SOUND AND COMPLETE for propositional logic, not single-step.
- wrong=0 is structural: an exact tautology check refuses (LogicError) on
malformed / out-of-decidable-regime (quantified/predicate) input, never guesses.
THE HONEST METRIC (evals/deductive_logic/):
- holdout v1 (500 cases): 500 correct / 0 WRONG, incl. 227 non-trivial deductions
(117 entailed + 110 refuted). dev (200): 200/0.
- Gold from an INDEPENDENT truth-table oracle (oracle.py) sharing zero code with
the engine. 8,000-case fuzz across two independent decision procedures:
0 disagreements. This is the soundness evidence the GSM8K composer could never
produce (it could not separate its 2 right from its 87 wrong answers).
- contract.md states the load-bearing honesty boundary: PROPOSITIONAL ONLY, and
given-formulas (NL->logic grounding is a separate later layer, kept out of scope
so we do not re-step on the GSM8K natural-language rake).
TESTS (17, all green): classic inference shapes (MP, multi-hop chain, modus
tollens, disjunctive/hypothetical syllogism, conjunctive rules, genuine unknown),
refusal boundary (inconsistent / quantified / predicate / malformed), and a
deterministic engine-vs-oracle fuzz cross-check.
Pure new module — does NOT touch serving. Smoke 73 passed; invariants 40 passed.
Phase 2.3: the first inference rule + the wrong=0 mechanism for proofs.
- generate/proof_chain/rules.py: evaluate_modus_ponens / evaluate_proof_conclusion.
Proof-layer dispatch (Option B) over proposition FORMULAS via the canonicalizer;
never touches check_admissibility/_resolve_dep_units (proofs have no units).
Disagreement rule = the select_self_verified twin: pool ALL admissible single-step
MP derivations, require a unique canonical key == declared conclusion. Pooling (not
filter-to-declared-first) is the soundness mechanism.
- generate/logic_canonical.py: parse_top_implication (+ _unparse) — recovers an
implication's syntactic antecedent/consequent (the ROBDD form doesn't preserve it).
- Closed typed-reason set; the corpus's finer labels consolidate (6 disagreement
refuse-labels -> conclusion_disagreement; 4 antecedent-flavor labels ->
unestablished_antecedent — same redundancy, same mechanism-makes-one-distinction
principle).
- Honesty boundary (exact scope): guarantees a unique conclusion among SINGLE-STEP MP
over the premises, NOT "uniquely entailed" by all strategies.
Cross-check: all 24 GPT-5.5 adversarial corpus cases agree on OUTCOME against the real
rule (no rule bug / no corpus outcome-misread); reasons consolidate as above.
Mutation: filter-to-declared-first makes DISAGREE-007/010 wrongly admit -> pooling
tests fail (pooling load-bearing).
Drive-by fix (cleanup-as-you-find): merged ADR-0204 ProofNode.__post_init__ was
dedented to module level -> all ProofNode validation was silently DEAD (smoke skips
the dedicated test file; the smoke != full-suite hazard). Re-indented; validation
restored.
Additive (math lane untouched). Full binding-graph surface green; smoke 67.
Phase 2.2, structure only (no inference rule — modus_ponens is 2.3). Translates a
Proof into a SemanticSymbolicBindingGraph; the ADR-0203 acyclicity guard + ADR-0132
referential integrity fire at construction.
- generate/proof_chain/model.py: the one canonical proof input shape (ProofNode/Proof
+ proof_from_premises desugaring of the corpus premises/conclusion shape).
- generate/proof_chain/builder.py: build_proof_graph — node→symbol+equation;
canonical_key→rhs_canonical, depends_on→dependencies, rule→operation_kind;
premises = empty-deps/op="premise"; unit_proof=PROOF_NO_UNIT, admissibility="pending";
conclusion tracked as conclusion_symbol_id.
- tests: 9 — valid DAG (PC-MP-001 desugared) + multistep construct; PC-CYCLE-001
refuses THROUGH the real builder (circular_dependency); canonical_key round-trips
byte-identical + equivalent formulas share rhs_canonical; admissibility-dispatch
confirmation; self/dangling refusals; out-of-regime node refuses. Mutation-verified
(drop dep-wiring -> cycle admitted -> test fails).
Admissibility dispatch confirmed graceful on proof operation_kinds: unknown kinds
-> AdmissibilityError(unknown_operation), unitless deps -> unit_unbound; NEVER
misroutes into _check_additive. Named 2.3 constraint: check_admissibility runs
_resolve_dep_units before dispatch, so modus_ponens must bypass unit-resolution.
Open items named for 2.3 (ADR-0204): conclusion typing (BoundUnknown revisit),
semantic_role="unknown" (closed vocab has no "proposition"), unit_proof sentinel.
Additive (first consumer; math lane untouched). Full binding-graph surface green;
smoke 67. Honesty boundary: through 2.3, sound over declared atoms, not grounded in input.
