His section on contains the famous exercise: "A topological space is T1 iff every singleton is closed." That is the warm-up . The final exercise in that section usually takes an hour.
If your professor mentions "the straight line with two origins" or "the book of Dugundji," you need this PDF. Topology -Dugundji-.pdf
The book "Topology - Dugundji -.pdf" has had a significant impact on the field of topology and mathematics in general. The book has been widely used as a reference and textbook in universities and research institutions around the world. The book's comprehensive treatment of topological spaces has made it an essential resource for researchers and students looking to gain a deeper understanding of the subject. His section on contains the famous exercise: "A