Whether a block with this coverage is authoritative for a query.
Whether a block with this coverage is authoritative for a query.
The recursion mirrors SubscriptionSupport.isIndexed, and for the same reasons: a union is covered only if every arm is, because the events we would miss are exactly the ones the uncovered arm would have found; an intersection needs just one covered arm, because that arm's results contain every candidate and the other arm post-filters data already in hand.