---
tag: 0XMEM406JM
kind: concept
name: Semigroup
msc: [20M10]
sources:
  - url: https://en.wikipedia.org/wiki/Semigroup
    locator: Definition
same_as:
  wikidata: Q207348
  wikipedia: Semigroup
---

## Summary

A semigroup is a set with an associative binary operation.
It need not have an identity element or inverses.