# checkmate (other-set)

Walls set by another so that no action within its reach keeps a thing inside its window; the window ends while the thing persists.

- Computed level: L15 (depth in the emergence graph, not abstraction)
- Status: published  ·  Domain: agency

## Emergence
**Emerges from:** [wall](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-wall.range-end), [set](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-set.fix), [action](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-action.deed), [reach](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-reach.action), [keep](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-keep.maintenance), [inside](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-inside.spatial), [window](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-window.range), [change](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-change.process), [persist](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-persist.continue), [power](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-power.over), [model](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-model.representation), [time](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-time.dimension)

**Through:** The opponent's pieces set walls on each square the king could go to and on the one it stands on; a model of the position lists each action and finds each outside the window. The game ends on that reading, and the king is never taken.

**Novel properties:**
- an end read from the model before it happens
- a loss in which no part is removed
- power that works by closing each exit at the same time

## Examples
- A chess game ends at checkmate: the king is attacked and no legal move removes the attack, and the king itself is never captured. *(chess)*

## Used by
- [smothered mate](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-smothered-mate.self-set) (L16)

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