---
tag: 01RVCMSN5N
kind: concept
name: Surjective function
aliases: [surjection, onto-function]
msc: ["03E20"]
sources:
  - url: https://en.wikipedia.org/wiki/Surjective_function
    locator: lead section
same_as:
  wikidata: Q229102
  wikipedia: Surjective function
---

## Summary

A function is surjective when each element of the codomain is a value of the function.