Research proof index

Bridge from Response.erroringPolicies membership back to the evaluator: if a policy id appears in the erroring set produced by isAuthorized, then some policy in ps with that id genuinely errored on evaluation. Because policy ids need not be unique, this recovers a policy with the id, not necessarily a specific one.

If a set of policies is well-typed (valid) with respect to the schema according to the validator, and the input request and entities are consistent with the schema, then evaluating a policy in this set either produces a boolean value, or throws an error of type entityDoesNotExist, extensionError, or arithBoundsError. These errors cannot be protected...

Response-level form of validation_is_sound: for a validated policy set with unique policy ids, every policy in the authorizer's erroringPolicies errored with one of the three errors validation cannot rule out (entityDoesNotExist, extensionError, arithBoundsError). Uniqueness of ids (PolicyIdsUnique, as in `determining_erroring_disjoint_when_...