"General Topology, also known as point-set topology, is a branch of mathematics that studies the properties of topological spaces. It is a fundamental area of study in mathematics, with applications in analysis, algebra, and geometry.
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The famous hierarchy: ( T_0, T_1, T_2 ) (Hausdorff), regular (( T_3 )), and normal (( T_4 )) spaces. Long explains why Hausdorff spaces are essential for uniqueness of limits and why normal spaces are required for Urysohn’s metrization theorem (introduced later in exercises). an introduction to general topology paul e long pdf link
There is no free or legal direct PDF download link available for Paul E. Long's textbook, as the book is still protected by copyright.
5. Look for open alternatives
If you cannot find Long’s book, consider these free and legal topology texts: "General Topology, also known as point-set topology, is
is available for users to track copies and potential borrowing options. Google Books : Provides a limited preview and bibliographic information for reference. Internet Archive An introduction to general topology : Long, Paul E
The Foundations: A deep dive into set theory and basic topological notions. Long explains why Hausdorff spaces are essential for
Alternative Resources:
Internet Archive: You can borrow the full 1971 edition for digital reading.