Source: wikibot/pi-system
= Pi-system
{wiki=Pi-system}
A Pi-system is a concept from measure theory, a branch of mathematics that deals with the formalization of concepts like size and probability. A Pi-system (or π-system) is specifically a collection of sets that has some special properties: 1. **Closure Under Intersection**: If you have two sets \\( A \\) and \\( B \\) in the Pi-system, then their intersection \\( A \\cap B \\) is also in the Pi-system.