Munkres Topology Chapter 3 Solutions

GitHub repository here, HTML versions here, and PDF version here.

Contents

Chapter 1. Set Theory and Logic

Chapter 2. Topological Spaces and Continuous Functions

  1. Topological Spaces
  2. Basis for a Topology
  3. The Order Topology
  4. The Product Topology on X × Y
  5. The Subspace Topology
  6. Closed Sets and Limit Point
  7. Continuous Functions
  8. The Product Topology
  9. The Metric Topology
  10. The Metric Topology (continued)
  11. The Quotient Topology

Chapter 3. Connectedness and Compactness

  1. Connected Spaces
  2. Connected Subspaces of the Real Line
  3. Components and Local Connectedness
  4. Compact Spaces
  5. Compact Subspaces of the Real Line
  6. Limit Point Compactness
  7. Local Compactness

Chapter 4. Countability and Separation Axioms

  1. The Countability Axioms
  2. The Separation Axioms
  3. Normal Spaces
  4. The Urysohn Lemma
  5. The Urysohn Metrization Theorem
  6. The Tietze Extension Theorem
  7. Imbeddings of Manifolds

Chapter 5. The Tychonoff Theorem

  1. The Tychonoff Theorem
  2. The Stone-Čech Compactification

Chapter 6. Metrization Theorems and Paracompactness

  1. Local Finiteness
  2. The Nagata-Smirnov Metrization Theorem
  3. Paracompactness
  4. The Smirnov Metrization Theorem

Chapter 7. Complete Metric Spaces and Function Spaces

  1. Complete Metric Spaces
  2. A Space-Filling Curve
  3. Compactness in Metric Spaces
  4. Pointwise and Compact Convergence
  5. Ascoli’s Theorem

Chapter 8. Baire Spaces and Dimension Theory

  1. Baire Spaces
  2. A Nowhere-Differentiable Function
  3. Introduction to Dimension Theory

Chapter 9. The Fundamental Group

  1. Homotopy of Paths
  2. The Fundamental Group
  3. Covering Spaces
  4. The Fundamental Group of the Circle
  5. Retractions and Fixed Points
  6. The Fundamental Theorem of Algebra
  7. The Borsuk-Ulam Theorem
  8. Deformation Retracts and Homotopy Type
  9. The Fundamental Group of Sn
  10. Fundamental Groups of Some Surfaces

Chapter 10. Separation Theorems in the Plane

  1. The Jordan Separation Theorem
  2. Invariance of Domain
  3. The Jordan Curve Theorem
  4. Imbedding Graphs in the Plane
  5. The Winding Number of a Simple Closed Curve
  6. The Cauchy Integral Formula

Chapter 11. The Seifert-van Kampen Theorem

  1. Direct Sums of Abelian Groups
  2. Free Products of Groups
  3. Free Groups
  4. The Seifert-van Kampen Theorem
  5. The Fundamental Group of a Wedge of Circles
  6. Adjoining a Two-cell
  7. The Fundamental Groups of the Torus and the Dunce Cap

Chapter 12. Classification of Surfaces

  1. Fundamental Groups of Surfaces
  2. Homology of Surfaces
  3. Cutting and Pasting
  4. The Classification Theorem
  5. Constructing Compact Surfaces

Chapter 13. Classification of Covering Spaces

  1. Equivalence of Covering Spaces
  2. The Universal Covering Space
  3. Covering Transformations
  4. Existence of Covering Spaces

Working problems is a crucial part of learning mathematics. No one can learn topology merely by poring over the definitions, theorems, and examples that are worked out in the text. One must work part of it out for oneself. To provide that opportunity is the purpose of the exercises.

Let be a collection of connected subspaces of ; let be a connected subspace of . Show that if for all , then is connected.

If there is a separation of the union, then and all lie within or (Lemma 23.2). Suppose, , then each , and is empty. Contradiction.

Alternatively, the connected (by Theorem 23.3) subspaces share a point (apply Theorem 23.3 again).

Below are links to answers and solutions for exercises in the Munkres (2000) Topology, Second Edition.

Enjoy!

Here you can find my written solutions to exercises of the book Topology, by James Munkres, 2nd edition. They contain all exercises from the following chapters:

  • Chapter 2 – Topological Spaces and Continuous Functions,
  • Chapter 3 – Connectedness and Compactness.

Unfortunately, I do not plan to write down solutions to any other chapter in the future.

This is not an official solution manual.

PDF Links:

Chapter 2 – Topological Spaces and Continuous Functions. (Last Updated: 1 January 2021.)

Chapter 3 – Connectedness and Compactness. (Last Updated: 1 January 2021.)

Try to do the exercises by yourself first. Do not just copy solutions.

Please be aware that I wrote down these solutions while I was still an undergraduate student some time ago, so they are more likely to contain errors. Please send comments, suggestions, corrections of errors/typos, etc, by e-mail, or as a comment in this webpage.

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