# relevance (core)

a parameter whose drift moves a wall

- Computed level: L12 (depth in the emergence graph, not abstraction)
- Status: review  ·  Domain: abstract  ·  Arena: general

## Emergence
**Emerges from:** [parameter](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-parameter.condition), [drift](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-drift.aimless), [wall](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-wall.range-end), [motion](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-motion.movement)

**Through:** The aimless drift of a condition parameter imparts movement to a range-end wall.

**Novel properties:**
- directed wall motion
- parameter-driven boundary shift

## Examples
- The 2021 Suez Canal blockage halted 12% of global trade until the Ever Given was refloated after six days. *(economics)*
- In 2019, the Hubble Space Telescope entered safe mode when a gyroscope failed, suspending observations for weeks. *(engineering)*
- The 1986 Chernobyl disaster released isotopes that rendered a 30-km radius uninhabitable for decades. *(physics)*

## Used by
- [across](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-across.spatial) (L14)
- [back](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-back.spatial) (L13)
- [collapse](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-collapse.failure) (L14)
- [page](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-page.sheet) (L16)
- [top](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-top.upper) (L13)
- [west](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-west.direction) (L15)

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*Canonical: https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-relevance.core*  
*Structured data: https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-relevance.core.json*  
*Every definition provably resolves to space, time, energy and pattern.*