nb-02 exercise — solution

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Bob’s file: disability_badge(bob) + fraud_flag(bob), nothing else.

1. Status — and is he refused?

NEITHER. The badge supports eligibility through BadgeEligibility, but the defeater FraudBlocksBadge removes that support without deriving the negation (defeat permit_eligible(a) is not then not permit_eligible(a) — compare FraudBlocksBadge (lines 47–51) with FinesRefusal (lines 30–34) in packs/examples/language-demo/permits/package.law). With support removed and no denial derived, neither side has support.

Bob is not refused. A refusal is FALSE_ONLY, which needs a derived negation winning — as in the suite test defeater removes support without negation (tests/permits.lawtest, lines 48–56, expect truth_status == NEITHER). Recording “refused for fraud” would invent a conclusion the engine never drew; the honest record is “eligibility undecided”.

2. Single change to eligibility

Remove fraud_flag(bob) from the file (equivalently: the fraud record is withdrawn or rebutted, so the defeater no longer fires). The badge’s support then stands unopposed through BadgeEligibility, and the status becomes TRUE_ONLY.

Checked: a scratch scenario with only disability_badge(bob) on file evaluates permit_eligible(bob) to TRUE_ONLY (temporary copy of the permits package with an added probe scenario; law test on the copy: all scenarios passed, including the badge-alone probe).