---
tag: 033DA1WE8Y
kind: concept
name: Projection
aliases: [idempotent-operator]
msc: [15A04]
sources:
  - url: https://en.wikipedia.org/wiki/Projection_(linear_algebra)
    locator: Definitions
same_as:
  wikidata: Q519967
  wikipedia: Projection (linear algebra)
---

## Summary

A projection is a linear map from a vector space to itself that is equal to its own square.
It projects the space onto its image along its kernel.