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Algebraic Topology

Algebraic Topology

Oct 10, 20261 min read

Introduction

Algebraic topology turns qualitative, flexible spaces into rigorous algebraic objects, enabling deep insights into shapes, holes, connectivity, and more—and impacts fields from geometry to data science to physics.

algebraic_topology

Contents

Fundamental Groups and Covering Spaces

Homotopy Types
Operations on Spaces
The Fundamental Group
van Kampen’s Theorem
CW Complexes
Covering Spaces
Fundamental Theorem of Covering Spaces
The Galois Correspondence Theorem
Deck Transformations and Normal Covers
Covering Space Actions

Homology

Delta Complexes
Singular Homology
Reduced Homology
Exact Sequences and Relative Homology
Long Exact Sequence of a Good Pair
Degree and Local Homology
Cellular Homology
Euler Characteristics and Mayer-Vietoris Sequence
Simplicial Sets

Cohomology

Formalism of Homology and Cohomology
Singular Cohomology
Projective Resolution of Modules
Universal Coefficient Theorem
Cup Product and Ring Structure
The Künneth formula
Cap Product and Poincaré Duality

More …

Topological Data Analysis

  • Oct 10, 2026

    Topological K-Theory

    • Oct 10, 2026

      Cap Product and Poincaré Duality

      • Oct 10, 2026

        Cup Product and Ring Structure

        • Oct 10, 2026

          Deck Transformations and Normal Covers

          • covering-spaces
          • algebraic-topology
        • Oct 10, 2026

          Euler Characteristics and Mayer-Vietoris Sequence

          • Oct 10, 2026

            Long Exact Sequence of a Good Pair

            • Oct 10, 2026

              Operations on Spaces

              • Oct 10, 2026

                Simplicial Sets

                • Oct 10, 2026

                  Singular Cohomology

                  • Oct 10, 2026

                    The Fundamental Group

                    • fundamental-group
                    • algebraic-topology
                    • fundamental-group-of-torus
                    • simply-connectedness
                    • brouwer-fixed-point-theorem
                  • Oct 10, 2026

                    The Künneth formula

                    • Oct 10, 2026

                      van Kampen's Theorem

                      • Oct 23, 2025

                        Projective Resolution of Modules

                        • algebraic-topology
                        • algebra
                        • cohomology
                        • homological-algebra
                        • functors
                      • Oct 23, 2025

                        Universal Coefficient Theorem

                        • Oct 22, 2025

                          Formalism of Homology and Cohomology

                          • algebraic-topology
                          • homology
                          • category-theory
                          • cohomology
                          • functors
                        • Oct 02, 2025

                          Degree and Local Homology

                          • algebraic_topology
                          • homology
                        • Sep 30, 2025

                          Cellular Homology

                          • algebraic-topology
                          • homology
                          • cw-complex
                          • euler-characteristic
                        • Sep 22, 2025

                          Reduced Homology

                          • algebraic-topology
                          • homology
                        • Sep 21, 2025

                          Singular Homology

                          • Sep 15, 2025

                            Delta Complexes

                            • homology-of-torus
                          • Aug 25, 2025

                            The Galois Correspondence Theorem

                            • algebraic-topology
                            • covering-spaces
                            • fundamental-group
                          • Aug 23, 2025

                            Homotopy Types

                            • homotopy
                            • algebraic-topology
                          • Aug 21, 2025

                            Covering Space Actions

                            • covering-spaces
                          • Aug 21, 2025

                            Covering Spaces

                            • covering-spaces
                            • algebraic-topology
                          • Aug 20, 2025

                            Fundamental Theorem of Covering Spaces

                            • covering-spaces
                            • fundamental-group
                            • algebraic-topology
                          • Aug 11, 2025

                            CW Complexes

                            • algebraic-topology
                            • cw-complex
                            • fundamental-group
                            • euler-characteristic
                            • real-projective-spaces
                          • Feb 11, 2025

                            Exact Sequences and Relative Homology

                            • diagram-chase
                            • exact-sequence

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