Any uncountable set X with co-finite topology is not first countable and so not second countable

In this video we will discuss an important theorem of topology the statement of this theorem is that Theorem 7.9.1: "Any uncountable set X with co-finite topology is not first countable and so not second countable" we understand each and every concept of this theorem & make sure you will understand it conceptually. Link of complete Playlist of Topology.    • Topology on a Set | Its Conditions & Examp...   #7.9.1Theorem #UncountableSetwithCo-finiteTopology If you feel any doubt about this theorem then you will ask me through comments... If you understand my videos then please like and share these videos...... THANK YOU