# Stated Invariant

> A design rule that an invariant a topology relies on is written with its property in a form that could be false, the set it ranges over, the parties it binds and the thing that would object if it stopped holding.

Record: `architecture:stated-invariant`
Kind: principle
Layer: [Execution Core](https://banes-lab.com/records/layer/execution-core.md)
Severity: mandatory
Scope: topology, coordination
Canonical: https://banes-lab.com/ontology#architecture-stated-invariant

Listed in [Architecture principles](https://banes-lab.com/api/records/architecture.md), after [Space-Based Architecture](https://banes-lab.com/records/architecture/space-based-architecture.md) and before [Derived Record State](https://banes-lab.com/records/architecture/derived-record-state.md).

## Repair

- Refactored by: Name the Objector, or Mark the Invariant Unheld and Every Derivation Resting on It
- Detected by: an invariant with no objector, or one that names no set or no bound party
- Violated by: relying on a property that nothing would notice losing, or stating it in a surface the bound parties never receive
- Measured by: invariants stated without an objector and not marked unheld
- Enforced by: coordination review

## Requires

- [Coordination Surface](https://banes-lab.com/records/lexicon/coordination-surface.md)

## Reinforces

- [Fitness Functions](https://banes-lab.com/records/architecture/fitness-functions.md)

## Enables

- [Traceable Guarantee](https://banes-lab.com/records/lexicon/traceable-guarantee.md)

## Conflicts with

- [Contradicted Invariant](https://banes-lab.com/records/architecture/contradicted-invariant.md)

## Severity

- [mandatory](https://banes-lab.com/records/vocabulary/severity-mandatory.md)

## Category

- [Coordination Surfaces](https://banes-lab.com/records/architecture-category/coordination-surfaces.md)

## Reinforced by

- [Operand-Free Outcome Surface](https://banes-lab.com/records/architecture/operand-free-outcome-surface.md)

## Linked from

- [Orchestration invariants](https://banes-lab.com/pag/orchestration/orchestration-invariants.md)
- [Stating an invariant](https://banes-lab.com/disciplined-methodology/collaborate/stating-an-invariant.md)
- [Architecture Review / Evolution / Governance Artifacts](https://banes-lab.com/ontology/principles/architecture-category-architecture-review-evolution-governance-artifacts.md)
- [Coordination Surfaces](https://banes-lab.com/ontology/principles/architecture-category-coordination-surfaces.md)
- [Coordination Surfaces](https://banes-lab.com/ontology/lexicon/lexicon-category-coordination-surfaces.md)
- [Severity levels](https://banes-lab.com/ontology/schema/the-vocabulary-severity.md)

## Evidence in the code

- [models/coordination.model.md](https://banes-lab.com/source/coordination/models/coordination.model.md.md)