---
tag: A0K4H2G578
kind: concept
name: Sunflower (mathematics)
aliases: [delta-lemma, delta-system, delta-system-lemma, sunflower-conjecture]
sources:
  - wikipedia: en:8208248@r1372848827
    locator: Sunflower (mathematics)
    note: adopted
    mention: wikipedia://en/8208248
    sections: [Summary]
same_as:
  wikidata: Q423986
  wikipedia: Sunflower (mathematics)
inventory: [9JH1BV510W]
---

## Summary

In the mathematical fields of set theory and extremal combinatorics, a **sunflower** or **$\Delta$-system** is a collection of [[sets|0BSJ7RQ9BW]] in which the [[intersection|0ZNMMA9TF5]] of any two distinct sets is the same. This common intersection is called the **kernel** of the sunflower.