MathProblemGraph.__post_init__ now raises MathGraphError when two
InitialPossession entries share the same (entity, unit) key but
declare different quantity values.
Pre-fix behavior surfaced by 2026-05-28 ADR-0174 Phase 3 post-merge
diagnostic: math_solver.solve() line 207 used last-write-wins dict
assignment when consolidating initial state. Two contradictory
inputs would silently overwrite without trace:
'Sam has 5 marbles. Sam has 3 marbles. How many marbles does Sam have?'
→ returned 3.0 (wrong=0 violation: definite answer from
contradictory input)
Post-fix: same input refuses with 'no branch produced a solvable
graph' — refusal-preferring discipline as wrong=0 doctrine requires.
Identical duplicates (same value) are admitted as redundant (no
contradiction). Different units for same actor admitted. Different
actors for same unit admitted. Single-value cases (the dominant
real-world pattern) unchanged.
This is an extraction-layer hazard discovered while investigating
Phase 3b scope: Phase 3b compound-clause held hypotheses would
emit multiple CandidateInitial entries per sentence, exercising
exactly this consolidation path. Fixing the silent overwrite NOW
ensures Phase 3b admission doesn't silently produce wrong answers.
Acceptance:
- 4 new tests in TestContradictoryInitialPossessionsRefuse
- 165/165 test_math_problem_graph tests pass (was 161/161)
- Smoke 67/67, packs 141/141 unchanged
- train_sample 3/47/0 unchanged (no real case exercised the
overwrite — but the hazard was latent)
References: CLAUDE.md §Lookback Review Discipline (the doctrine
that surfaced this), CLAUDE.md §Non-Negotiable Field Invariant
(make illegal states difficult to represent).
Second parser-expansion ADR after ADR-0122 rate/per-unit. Adds the
comparison algebra substrate (Comparison dataclass + compare_additive /
compare_multiplicative operation kinds + parser patterns + solver /
verifier / pack lemmas) mirroring the substrate-only / lift-deferred
pattern ADR-0122 established.
Substrate
- Comparison(reference_actor, delta: Quantity|None, factor: float|None,
direction: Literal[more,fewer,times,fraction]) frozen dataclass with
direction-discriminated delta/factor enforcement and self-reference
refusal at the Operation boundary
- compare_additive + compare_multiplicative operation kinds admitted in
VALID_OPERATION_KINDS; Operation.operand widened to Quantity|Comparison
with kind-discriminated type enforcement; entity-set validation extended
to cover Comparison.reference_actor
- Parser: _COMPARE_ADDITIVE_RE (more/fewer/less), _COMPARE_TWICE_RE,
_COMPARE_N_TIMES_RE, _COMPARE_HALF_RE happy-path patterns + 5
refusal patterns (ambiguous 'N times more', age comparisons,
combined-with-aggregation, nested additive+multiplicative); inserted
before _try_initial so leading 'has <N>' shape is not greedily
consumed as initial possession with unit='more'/'fewer'
- Solver: _apply_compare_additive (refuses on missing reference state,
overwrite, negative result); _apply_compare_multiplicative (refuses
on missing reference, ambiguous multi-unit reference, overwrite);
unit comes from delta.unit (additive) or reference's unique unit
(multiplicative)
- Verifier: _verify_compare_additive_step + _verify_compare_multiplicative_step
byte-equal replay; tamper-detects after_value, direction, factor
- Pack: en-arith-006 compare_additive + en-arith-007 compare_multiplicative
lemmas + glosses; SHA-256 checksums refreshed; manifest 1.0.0 -> 1.1.0;
provenance tagged adr-0123:comparison_extension:2026-05-23
Measurement (honest; from Gemini empirical sealed run on parallel surface
branch with this substrate)
- Sealed GSM8K correct_rate: 0/1319 (substrate matches zero real cases
alone). Validates the ADR-0122 multi-construction barrier prediction:
comparison constructions in GSM8K rarely appear alone — they bind with
rate (ADR-0124), percentage (ADR-0125), aggregation (ADR-0126), or
conditional ('if') clauses. First lift signal requires composition.
- Sealed GSM8K wrong: 0 (load-bearing positive claim; ADR-0114a
Obligation #4 preserved across all 1,319 sealed problems)
- Regression safety: 0 — all 913 non-comparison cases continue to
refuse exactly as before (refused_parser), no greedy consumption by
the new comparison patterns
Surface-form catalog (from Gemini Task 2 survey, see ADR doc) covers
6 primary forms across Groups A/B/C; Groups D (age), E (combined with
aggregation), F (nested additive+multiplicative) refused as out-of-scope
with typed ParseError naming the missing companion ADR.
Branch isolation
- Landed via dedicated worktree (feat/adr-0123-substrate from origin/main)
after a file-race on the shared umbrella branch. Companion surface +
scaffolding (realizer, ADR doc, tests, README) lands separately as
feat/adr-0123-surface; orchestrator merges both into the umbrella
feat/adr-0123-comparison-phrasing.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
First Phase of ADR-0114's expert-capability roadmap. Decomposed into four
sub-phases so each lands as its own auditable step:
1.1 schema + 5 seed cases + invariants ← this commit
1.2 45 more dev-set cases ← delegated (Codex)
1.3 the parser itself ← exit: ≥0.90 on dev set
1.4 runtime binding ← if non-trivial
What landed
- generate/math_problem_graph.py — typed dataclasses (Quantity,
InitialPossession, Operation, Unknown, MathProblemGraph) + frozen
validation + canonical_bytes() byte-deterministic serialization +
graph_from_dict roundtrip.
- evals/gsm8k_parser_dev/cases.jsonl — 5 seed cases (gpd-001..005)
covering single-add, single-subtract, multi-step, two-entity
transfer, and multi-entity sum constructions. Every case carries a
ground_truth_graph and the documented patterns it exercises.
- evals/gsm8k_parser_dev/README.md — authoring contract: schema,
pattern registry, canonicalization rules, Phase 1.1 scope boundary,
hand-solving rubric, distribution target for the remaining 45
cases. This is the spec Phase 1.2 authors work against.
- tests/test_math_problem_graph.py — 26 cases pinning four invariants:
round-trip byte equality, canonical_bytes() determinism, schema
rejection of malformed graphs, and ground_truth_graph ↔
expected_answer agreement (a hand-solver inside the test module
falsifies mis-authored cases).
Why this is sticky
The Phase 1.1 schema is load-bearing for Phase 1.2 (the 45 authored
cases will be written against it) AND Phase 1.3 (the parser will be
graded byte-equal against ground-truth graphs in this schema). Changing
the schema after Phase 1.2 lands requires an amendment ADR + rewriting
authored cases. The schema choices here are intentionally conservative.
Tests: 26/26 new; 67/67 smoke green.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Shay