# Choose the kind of a relation

## Intent

I want to name the nature of a fact without attributing evidential force to metadata.

The same truth holds under a different kind.

## Wrong form and why it stays silent

```law title="Incorrect form"
relation received(d: Letter) kind empirical;
fiction Receipt strict { for d: Letter; when delivered(d); deem received(d); }
```

kind itself does not change truth. Warning E1309 shows a wrong choice of an empirical fiction head; it does not block derivation.

## Correct form

```law
language "law.core" version "0.2";
package recipes.g.r09 version "0.1.0";
namespace "urn:recipe:g-concepts:09";

entity Letter;
relation delivered(d: Letter);
relation received(d: Letter) kind institutional;
fiction Receipt strict { for d: Letter; when delivered(d); deem received(d); }
```

## Frozen execution scene

| Facts on 13.09.2026 | Question | Answer |
|---|---|---|
| institutional head | `truth(received(entity_ref("urn:recipe:g-concepts:09:p")))` | `truth_status == TRUE_ONLY;` / `COMPUTED` |
| no producer | `truth(received(entity_ref("urn:recipe:g-concepts:09:p")))` | `truth_status == NEITHER;` / `COMPUTED` |

```law
test "institutional head derives" {
    given {
        context {
            legal_time @2026-09-13;
            decision_time @2026-09-13T09:00:00+05:00;
            knowledge_time @2026-09-13T09:00:00+05:00;
            timezone "Asia/Almaty";
        }
        assert delivered(entity_ref("urn:recipe:g-concepts:09:p"));
    }
    evaluate truth(received(entity_ref("urn:recipe:g-concepts:09:p")));
    expect truth_status == TRUE_ONLY;
    expect evaluation_status == COMPUTED;
}
```

```law
test "no producer stays unknown" {
    given {
        context {
            legal_time @2026-09-13;
            decision_time @2026-09-13T09:00:00+05:00;
            knowledge_time @2026-09-13T09:00:00+05:00;
            timezone "Asia/Almaty";
        }

    }
    evaluate truth(received(entity_ref("urn:recipe:g-concepts:09:p")));
    expect truth_status == NEITHER;
    expect evaluation_status == COMPUTED;
}
```

kind institutional is replaced with empirical: E1309 warns, but truth remains TRUE_ONLY.

```law
test "empirical-head variant derives receipt directly" {
    given {
        context {
            legal_time @2026-09-13;
            decision_time @2026-09-13T09:00:00+05:00;
            knowledge_time @2026-09-13T09:00:00+05:00;
            timezone "Asia/Almaty";
        }
        assert delivered(entity_ref("urn:recipe:g-concepts:09:p"));
    }
    evaluate truth(received(entity_ref("urn:recipe:g-concepts:09:p")));
    expect truth_status == TRUE_ONLY;
    expect evaluation_status == COMPUTED;
}
```

```python
>>> import runpy
>>> check = runpy.run_path("docs/recipes/g-concepts/resources/check.py")
>>> check["check_variant"](https://github.com/arxohq/law/blob/master/docs/recipes/g-concepts/9)
'Г9: контрфактуал подтверждён; lawc = lawref'
```

## Counterfactual

Mutation `relation received(d: Letter) kind institutional;` → `relation received(d: Letter) kind empirical;`: LDC-E1309 (warning, exit code 0).

## Boundary

A policy may read kind, but this program has no such policy. The institutional label does not create source authority and does not turn an empirical observation into a reliable one.