Adds `teaching/math_claim_signature.py` with `lexical_claim_signature()`:
sha256 hex of a normalised lexical token, collapsing two refusal cases on
the same surface token into one teaching-corpus candidate.
Normalisation pipeline (documented in module, breaking-change surface):
1. Lowercase surface
2. Strip string.punctuation from both ends (!"#$%&'()*+,-./:;<=>?@[\]^_`{|}~)
3. Extract token from refusal_detail via r"no primitive or lexicon match for '([^']+)'"
4. Fallback: use stripped-lowercase surface if regex doesn't match
5. Canonical: "lexical:" + extracted_token
6. sha256 hex of UTF-8 bytes → 64-char lowercase hex
Also adds `teaching/math_contemplation.py` (W2-A adapter included as
union-merge; W2-A worktree was not yet dispatched):
- `audit_to_evidence()`: AuditRow iterable → MathReaderRefusalEvidence tuple
- `audit_problem_to_evidence()`: convenience wrapper for tests and W3-A
- Lexical evidence: claim_signature filled; evidence_hash recomputed to include it
- Non-lexical sub_types: claim_signature stays "" (deferred per ADR-0167 §Q1)
Real-data result on audit_brief_11.json:
- 14 distinct lexical tokens → 14 distinct signatures (no false collisions)
- No duplicate tokens in the 50-case sample; dedup logic verified deterministic
Wave 2, parallel with W2-C/D; depends on W1-A branch.
wrong=0 verified by passing regression suite.
Wave 2, parallel with W2-B/C/D. Implements the type-A→type-B converter
from AuditRow to MathReaderRefusalEvidence per ADR-0167 W2-A brief.
Deliverables:
- teaching/math_contemplation.py:
- audit_to_evidence(audit_rows): pure deterministic adapter, uses
SUB_TYPE_FOR_OPERATOR for subtype assignment, skips rows where
missing_operator is None, leaves claim_signature="" (W2-B will fill)
- audit_problem_to_evidence(problem_text, case_id): convenience wrapper
that runs the reader and adapts the output
- tests/test_math_contemplation_adapter.py: 8 tests covering
determinism, input-order preservation, sub-type mapping
exhaustiveness, distinct hashes across cases, empty input handling,
None-operator skip, and round-trip from problem text
Invariants:
- Deterministic across reruns (verified by determinism rerun)
- No I/O in adapter path
- Input order preserved (no internal sort)
- claim_signature == "" for all W2-A records (W2-B coordination)
Validation:
- tests/test_math_contemplation_adapter.py: 8 passed
- tests/test_math_evidence_schema.py: 11 passed (W1-A regression)
- tests/test_brief_11b_audit_artifact.py + step2_lexicon + brief_11_audit:
45 passed (regression)
- Determinism rerun: identical results
