Useful Links
Mathematics
Topology
Types and Properties of Spaces
Compactness
Definition and Examples
Definition of compactness as every open cover having a finite subcover.
Examples of compact spaces, such as closed intervals in \(\mathbb{R}\).
Non-examples to illustrate the importance of compactness in topology.
Compact Subspaces
Criteria and methods for proving subspaces are compact.
Relationship between compactness and closed subspaces.
Compactness in product spaces.
Tychonoff's Theorem
Statement and proof of Tychonoff's Theorem for the product of compact spaces.
Implications and applications of Tychonoff's Theorem in various branches of mathematics.
Heine-Borel Theorem
Statement of the Heine-Borel Theorem for Euclidean spaces.
Relationship between compactness, closedness, and boundedness in \(\mathbb{R}^n\).
Applications of the Heine-Borel Theorem in analysis and geometry.
Connectedness
Connected and Path-Connected Spaces
Definition of connected spaces and examples.
Definition of path-connectedness and examples.
Differences and relationships between connectedness and path-connectedness.
Components and Path Components
Definition and properties of connected components.
Role of path components in path-connected spaces.
Methods for determining components in topological spaces.
Intermediate Value Theorem
Application of connectedness in proving the Intermediate Value Theorem.
Examples illustrating the use of the theorem in real analysis.
Separation Axioms
T0, T1, T2 (Hausdorff) Spaces
Definitions and properties of the T0, T1, and T2 axioms.
Examples of spaces satisfying various separation axioms.
Importance of separation properties in convergence and function extension.
Regular and Normal Spaces
Definitions and characterizations of regular and normal spaces.
Examples and counterexamples of regular and normal spaces.
The role of Urysohn's Lemma in proving normality.
Urysohn's Lemma
Statement and proof of Urysohn's Lemma.
Applications of Urysohn's Lemma in the context of normal spaces.
Tietze Extension Theorem
Statement and proof of the Tietze Extension Theorem.
Conditions under which continuous functions can be extended.
Practical use of the Tietze Extension Theorem in analysis.
Metrizability
Metric Spaces
Definition and examples of metric spaces.
Relationships between metrics and topologies.
Properties of metric spaces regarding convergence and continuity.
Urysohn Metrization Theorem
Statement and significance of the Urysohn Metrization Theorem.
Criteria for a space to be metrizable.
Application of the theorem in identifying metrizable topological spaces.
Complete Metric Spaces
Definition and significance of completeness.
Famous examples of complete and incomplete metric spaces.
The use of Banach Fixed Point Theorem in complete metric spaces.
Compact-Open Topology
Definition of Compact-Open Topology
Introduction to the compact-open topology on function spaces.
Basis and subbasis for the compact-open topology.
Properties and Applications
Key properties including continuity and convergence in the compact-open topology.
Applications in functional analysis and topological dynamics.
Role in the study of function spaces and sequence spaces.
1. General Concepts
First Page
3. Algebraic Topology