# INVARIANT

> The record head · a property the topology relies on, with its set, its parties and its objector

Record: `pag:keyword-invariant`
Kind: keyword
Canonical: https://banes-lab.com/ontology/grammar#pag-keyword-invariant

Listed in [Grammar records](https://banes-lab.com/api/records/pag.md), after [COMPLETION](https://banes-lab.com/records/pag/keyword-completion.md) and before [PROPERTY](https://banes-lab.com/records/pag/keyword-property.md).

## Grounds

- [substrate-node:invariant](https://banes-lab.com/records/reasoning/substrate-node-invariant.md)
- [invariant:epi-reachable-check](https://banes-lab.com/records/reasoning/invariant-epi-reachable-check.md)

## Expresses

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

## Linked from

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