# V. Unknown, negation, closed lists

10 pages in this book.

| Page | What it is for |
|---|---|
| [Establish the absence of a registry record](/recipes/v-negation/registry-absence/) | I want to treat the absence of a licence as a negative fact only inside a complete registry. |
| [Submit a negative fact](/recipes/v-negation/negative-fact/) | I want to tell the case that a person is not insured. |
| [Apply a default after producers](/recipes/v-negation/default-unless-proven/) | I want to apply the ordinary order until the exception has positive support. |
| [Close a list before a residual norm](/recipes/v-negation/closed-list/) | I want to allow actions outside an exhaustive list of prohibitions. |
| [Distinguish an unknown sum from zero](/recipes/v-negation/missing-not-zero/) | I want to derive a zero sum only when completeness of an empty journal is confirmed. |
| [Use a disputed fact deliberately](/recipes/v-negation/consume-conflict/) | I want to order a review when there is positive support, even if the fact is contested. |
| [Walk a chain with strict recursion](/recipes/v-negation/recursive-chain/) | I want to derive reachability along a finite chain of relations. |
| [Count a completed set of conclusions](/recipes/v-negation/aggregate-barrier/) | I want to count reachable vertices after all producers have finished. |
| [Derive an explicit negative by a norm](/recipes/v-negation/negative-head/) | I want to derive the absence of a debt from an established discharge. |
| [Check every element of a finite set](/recipes/v-negation/finite-forall/) | I want to check all reachable elements after their set has completed. |