nb-25 solutions — Capstone case

← Back to lessonChapter 25 / 25 · Modeling practice · Worked solution

Exercise: Bob’s five values

Checkable against law test packs/examples/language-demo/capstone (9 checked, 9 passed, 0 failed). Tool law 0.1.0, language 0.2, semantics law.core/0.2, std 0.2.0. Identifiers and code as written.

Exercise: Bob’s five values

Bob files: resident with a registered car, twelve-month term, filed 1 March, no hold, single filing copy.

Answer:

1. capstone_ready(Bob) is TRUE_ONLY — residency plus car fires permit_eligible upstream (same shape as Ann’s resident driver is capstone-ready).
2. capstone_grant(Bob) is TRUE_ONLY — readiness holds and no capstone_hold blocks the defeasible grant (same shape as resident driver is granted without a hold; contrast a hold defeats the grant, which differs by exactly that one fact).
3. capstone_fee(12) is 120 EUR — twelve months at the shared MONTHLY_RATE of 10 EUR (same rate as capstone fee for three months at 30 EUR).
4. CapstoneTrack(12) is 0.2 — the first row matches (direct analogue of capstone track rewards the long term).
5. capstone_due(Bob, @2026-04-01) is TRUE_ONLY — thirty calendar days after the 1 March filing under CAPSTONE_DAYS (direct analogue of capstone deadline thirty days after filing).

Run law test packs/examples/language-demo/capstone: итого: 9 проверено, 9 прошли, 0 не прошли, 0 не исполнены; код 0 — all five predictions confirmed, suite green. The minimal change that would flip value 2 to NEITHER is adding one capstone_hold fact (cost 1, per the counterfactual in section 6 of the article).

Mini-exercise 1: no car, no grant

Checkable on a scratch copy: 9 shipped tests plus the new probe, 10 checked, 10 passed, 0 failed — or by shape against the shipped suite.

Answer: both NEITHER. Readiness needs the vehicle conjunct (without a car nothing is ready), and the grant needs readiness (probe: grant silent without a car). The choice is conjunction all the way down: no link fires on a partial file, so silence propagates from eligibility to grant.

Mini-exercise 2: Carol’s single copy

Checkable on a scratch copy (probe: single copy, no conflict), same shape as the deadline test.

Answer: TRUE_ONLY, no issue. A key with one value is satisfied, so no KEY_CONFLICT arises — the single-copy shape of capstone deadline thirty days after filing, which derives 1 April from one filing. The conflict in step 2 is a property of the doubled input, not of filing as such.

Mini-exercise 3: the hold lifts

Checkable by shape against the shipped pair.

Answer: TRUE_ONLY. The file returns to the granted without a hold shape: an unless defeater leaves no residue once its condition is gone. Contrast the naive strict denial, which would have written FALSE_ONLY into the record — silence lifts cleanly, denial would not.

Mini-exercise 4: Narrow decides

Checkable by shape against the appeals suite (7/7).

Answer: FALSE_ONLY. The Narrow rule reads only second_vehicle, so eligibility is irrelevant under it — the same FALSE_ONLY shape as the narrow reading test, which asserts the vehicle alone. Choosing Narrow means the second car decides against the permit no matter how strong the rest of the file is.

Mini-exercise 5: the 2026 rule asleep

Checkable by shape against the sourcetime suite (20/20).

Answer: NEITHER. The executed shape of before entry into force the 2026 rule is silent: the 2026 rule’s window has not opened at @2025-06-01, so it does not participate no matter how complete the facts are. The old notice is a different predicate — it holds in its window, but the question asked about the new one.

Integrative assignment: Bob’s nine values plus three twists

Checkable against the three section 4 commands: capstone 9/9, appeals 7/7, sourcetime 20/20, all green.

Answers:

1. capstone_ready(Bob) is TRUE_ONLY — resident driver is capstone-ready.
2. capstone_grant(Bob) is TRUE_ONLY — granted without a hold.
3. The 1 March filing is TRUE_ONLY with KEY_CONFLICT — the conflict pair; the key reports, it does not deny.
4. Under the hold the grant is NEITHER with readiness TRUE_ONLY — a hold defeats the grant plus the surviving readiness probe; the unless gates one link.
5. After the hold is lifted the grant is TRUE_ONLY — defeater removed, grant follows readiness again.
6. second_permit(Bob) under Narrow is FALSE_ONLY — Narrow reads only the second vehicle.
7. second_permit(Bob) under Broad is TRUE_ONLY — Broad with eligibility.
8. The 2025 eligibility_notice is NEITHER — the 2026 rule is silent before entry into force.
9. resident_admitted is NEITHER at January office knowledge, TRUE_ONLY at March knowledge — admission follows knowledge_time, and the decision-day pair shows no other clock substitutes.

Three twists — name the construct:

(a) A suspension that blocks while recorded and vanishes when cleared → unless on the grant (step 3: removal without denial, no residue). (b) Two defensible readings of one term → named interpretations under an exactly_one group with case-level selection (step 4: disagreement named, no silent default). (c) A proof dated before the filing that arrives after the decision → knowledge-gated admission via the evidence policy, not a legal_time shift (step 5: the proof’s date never was the question; the office’s knowledge is).