Duration of the online course: 24 hours and 16 minutes
New course
Unlock the essentials of algebraic topology with this free online course. Master key concepts and explore applications of homology theories and theorems.
In this free course, learn about
Foundations of Singular Homology
Eilenberg-Steenrod Axioms and Basic Consequences
Exact Sequences and Homotopy Invariance
Excision, Small Simplices, and Dimension Axiom
Low-Dimensional Homology and Hurewicz Theorem
Relative, Reduced Homology and Mayer-Vietoris
Suspension, Degree of Maps, and Klein Bottle
Topological Applications: Vector Fields and Dimension
Cellular Homology and Euler Characteristic
Homological Algebra: Projective Modules and Resolutions
Tensor Products, Tor, and Universal Coefficients
Course Description
Explore the fascinating world of algebraic topology with this comprehensive online course. Dive into the foundational concepts starting with an introduction to algebraic topology, laying the groundwork for understanding the intricate structures and principles that guide this mathematical domain.
Delve into the core subjects, including the definition of singular and relative singular homology, and grasp the Eilenberg-Steenrod axioms that serve as critical touchstones in homology theory. Learn to apply these axioms to compute homologies of spheres and understand important concepts like the snake lemma and the long exact sequence axiom.
Unravel the mysteries of homotopy invariance and the 5-lemma, explore the excision and dimension axioms, and gain insights into further nuances of the Eilenberg-Steenrod axioms. The course encourages students to explore singular homology in degree zero, understand relative homology as absolute homology, and appreciate the Hurewicz isomorphism.
The Mayer-Vietoris sequences and their application for pushouts are examined in depth, along with the suspension isomorphism and computations related to real-world objects like the Klein bottle. Delve into sophisticated mathematical theorems such as the Borsuk-Ulam and Ham-Sandwich Theorems. Discover the usefulness of cellular chain complexes, their computations, and how they relate back to singular homology.
Develop a deep understanding of the Euler characteristic, lens spaces, and projective modules. Grasp the fundamental theorem of homological algebra, alongside tensor products and their computations. Obtain thorough knowledge of the Tor functor and the universal coefficient theorem, and apply the Künneth theorem and acyclic models theorem to solve complex algebraic problems.
By the end of the course, students will have gained a robust understanding of algebraic topology, equipped with tools and techniques to tackle a wide range of problems with confidence.
Course content
Video class: 01 Introduction20m
Exercise: What is the main task of algebraic topology?
Video class: 02 Definition of singular homology1h03m
Exercise: What is an n-simplex?
Video class: 03 Definition of relative singular homology17m
Exercise: What New Concept Was Introduced in Relative Singular Homology?
Video class: 04 Eilenberg-Steenrod Axioms30m
Exercise: What is the primary use of the Eilenberg-Steenrod axioms in homology theory?
Video class: 05 Homology of spheres from the axioms44m
Exercise: What is the homology of a circle (S1)?
Video class: 06 Exemplary computation of an induced map25m
Exercise: What does the reflection map on spheres induce?
Video class: 07 The snake lemma39m
Exercise: What is the Snake Lemma in singular homology?
Video class: 08 The long exact sequence axiom in homology37m
Exercise: What is the main consequence of the Snake Lemma in singular homology?
Video class: 09 The homotopy invariance of singular homology1h00m
Exercise: What is the concept of homotopic invariance in singular homology?
Video class: 10 The 5-lemma08m
Exercise: What conclusion does the Five Lemma in homological algebra lead to?
Video class: 11 The excision axiom47m
Exercise: What is an essential aspect of the excision axiom in singular homology?
Video class: 12 The lemma of small simplices1h10m
Exercise: What is the primary purpose of barycentric subdivision in the proof of the small simplices lemma?
Video class: 13 The dimension axiom07m
Exercise: What is the result of the nth singular homology of a single point according to the dimension axiom?
Video class: 14 Further remarks on the Eilenberg-Steenrod axioms20m
Exercise: Which axiom does singular homology satisfy in relation to topological space decomposition?
Video class: 15 Singular homology in degree 018m
Exercise: What does the zeroth singular homology reveal about a topological space?
Video class: 16 The Hurewicz isomorphism48m
Exercise: What does the Hurriwich Theorem in Degree One relate in topology?
Video class: 17 The triple sequence14m
Exercise: What is the concept behind the triple sequence in topology?
Video class: 18 Relative homology as absolute homology47m
Exercise: What is the relationship between reduced and unreduced homology for a point?
Video class: 19 Mayer-Vietoris sequence16m
Exercise: What is the purpose of the Mayer-Vietoris sequence in algebraic topology?
Video class: 20 Mayer-Vietoris sequence for pushouts08m
Exercise: Understanding the Excision Axiom in Homology
Video class: 21 The suspension isomorphism11m
Exercise: What is the suspension isomorphism in homology?
Video class: 22 The degree of self-maps of the circle16m
Exercise: How does a map from the circle to itself behave in homology when mapped to its k-th power?
Video class: 23 The homology of the Klein bottle19m
Exercise: What is the first homology group of the Klein bottle?
Video class: 24 The homology of the Klein bottle (alternative method)12m
Exercise: Calculate First Homology Group of a Klein Bottle using Mayer-Vietoris Sequence
Video class: 25 Calm on earth (and spheres)14m
Exercise: What theorem is illustrated by the statement about wind on Earth?
Video class: 26 Invariance of domain45m
Exercise: What is the significance of the 'Jordan Curve Theorem' in topology?
Video class: 27 Invariance of dimension14m
Exercise: Understanding the Invariance of Dimension Theorem
Video class: 28 The Borsuk-Ulam theorem47m
Exercise: What is the main statement of the Borsuk-Ulam Theorem?
Video class: 29 The Ham-Sandwich Theorem25m
Exercise: What is the Ham Sandwich Theorem about?
Video class: 30 The cellular chain complex22m
Exercise: What is a benefit of using cellular homology over singular homology?
Video class: 31 Cellular homology computes singular homology36m
Exercise: What does the Cellular Chain Complex Compute?
Video class: 32 Incidence numbers of the cellular chain complex16m
Exercise: How is the nth cellular boundary operator expressed in terms of the incidence matrix?
Video class: 33 Differentials in the cellular chain complex29m
Exercise: Understanding incidence numbers and cellular chain complexes
Video class: 34 Easy examples of cellular homology28m
Exercise: What is the incidence number for cells in a cellular chain complex?
Video class: 35 Euler characteristic37m
Exercise: What is the Euler Characteristic of a Finite Planar Graph?
Video class: 36 Lens spaces52m
Exercise: What property distinguishes lens spaces
Video class: 37 Projective modules19m
Exercise: What Characterizes a Projective Module?
Video class: 38 Fundamental theorem of homological algebra37m
Exercise: What does the fundamental theorem of homological algebra state regarding projective resolutions?
Video class: 39 Tensor products38m
Exercise: What is the Canonical Way to Construct a Tensor Product in Homological Algebra?
Video class: 40 Left and right exactness37m
Exercise: What is the status of the Hom and Tensor functors in terms of exactness?
Video class: 41 Computations of tensor products34m
Exercise: What is the result of the tensor product of ? and ? over ? as ?-modules?
Video class: 42 The Tor functor56m
Exercise: What measures the failure of left exactness in tensor products?
Video class: 43 Universal coefficient theorem41m
Exercise: What does the Universal Coefficient Theorem (UCT) clarify in homological algebra?
Video class: 44 Künneth theorem47m
Exercise: What theorem helps compute homology of tensor products of chain complexes?
Video class: 45 Acyclic models theorem43m
Exercise: What is a homomorphism of RC modules?
Video class: 46 Applications of the universal coefficient and Künneth theorem19m
Exercise: What is the homology of the d-dimensional torus?