Submit a negative fact

Intention

I want to tell the case that a person is not insured.

Correct formFrozen execution sceneBoundary

Incorrect form and why it stays silent

Polarity is written before the atom. A field in the assertion body does not replace not:

Incorrect form

assert insured(person) { polarity negative; }

A second error is to negate the whole conjunction: not (registered(p) and insured(p)) is rejected.

Correct form

Arxo Law

language "law.core" version "0.2";
package recipes.v.r02 version "0.1.0";
namespace "urn:recipe:v-negation:02";

entity Person;
relation registered(p: Person);
relation insured(p: Person);
relation notice(p: Person);
rule Notice strict {
    for p: Person;
    when registered(p) and not insured(p);
    then notice(p);
}

Frozen execution scene

Facts	Question	Answer
registered(a), assert not insured(a)	notice(a)	TRUE_ONLY
registered(a), insured(a) { polarity negative; }	notice(a)	NEITHER
registered(a), no insured	notice(a)	NEITHER

explicit negative fact triggers notice

Arxo Law

test "explicit negative fact triggers notice" {
    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 registered(entity_ref("urn:recipe:v-negation:02:a"));
        assert not insured(entity_ref("urn:recipe:v-negation:02:a"));
    }
    evaluate truth(notice(entity_ref("urn:recipe:v-negation:02:a")));
    expect truth_status == TRUE_ONLY;
    expect applied(Notice);
}

polarity field is no negation

Arxo Law

test "polarity field is no negation" {
    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 registered(entity_ref("urn:recipe:v-negation:02:a"));
        assert insured(entity_ref("urn:recipe:v-negation:02:a")) { polarity negative; }
    }
    evaluate truth(notice(entity_ref("urn:recipe:v-negation:02:a")));
    expect truth_status == NEITHER;
    expect not applied(Notice);
}

Counterfactual

The two scene files differ in how the negative fact is written; the second keeps the wrong answer. teaches separately pins the ban on not over a conjunction (E1305).

Boundary

A negative fact must have its own ground; negating a compound formula is rejected.

Pitfall

polarity negative does not give negative support; the fix is assert not.