To understand closed sets it is important to know about open set and limit points.
Open sets : https://youtu.be/4X7BGy61TtQ
limit points : https://youtu.be/Z2q1L0nXJPE
For written notes do check my blog
https://mathcirclecoin.wordpress.com/2020/11/30/definition-of-closed-set-with-examples-and-theorems/
feel free to contact for any query on [email protected]
