18.901: Introduction to topology (Fall 2023)
The syllabus for this course is available here.
Lecture time: Tuesday and Thursday: 2:30 pm - 4:00 pm
Location: 2-105
Instructor Email: pieloch@mit.edu
Instructor Office Hours: See Canvas announcements
Problem Sets
- Problem set 1
Due Tuesday, September 12th, 2023 at 2:30 pm
- Problem set 2
Due Tuesday, September 19th, 2023 at 2:30 pm
- Problem set 3
Due Tuesday, September 26th, 2023 at 2:30 pm
- Problem set 4
Due Tuesday, October 3rd, 2023 at 2:30 pm
- Problem set 5
Students are not required to turn in this homework.
- Problem set 6
Due Tuesday, October 17th, 2023 at 2:30 pm
- Problem set 7
Due Tuesday, October 24th, 2023 at 2:30 pm
- Problem set 8
Due Tuesday, October 31st, 2023 at 2:30 pm
- Problem set 9
Due Tuesday, November 7th, 2023 at 2:30 pm
- Problem set 10
Students are not required to turn in this homework.
- Problem set 11
Due Tuesday, November 21st, 2023 at 2:30 pm
- Problem set 12
Due Tuesday, November 28th, 2023 at 2:30 pm
- Problem set 13
Due Tuesday, December 5th, 2023 at 2:30 pm
- Problem set 14
Students are not required to turn in this homework.
Exams
- Midterm 1:
- Time: Thursday, October 5th, 2023 at 2:30 pm - 4:00 pm
- Material covered: Lectures 1-8, but you will not be responsible for knowing the proofs of Urysohn's lemma and metrization theorem.
- Midterm 1, Midterm 1 Solutions
- Midterm 2:
- Time: Tuesday, November 14th, 2023 at 2:30 pm - 4:00 pm
- Material covered: Lectures 9-17.
- Midterm 2, Midterm 2 Solutions
- Final exam:
- Time: Wednesday, December 20th, 2023 at 9:00 am - 12:00 pm
- Material covered: Lectures 1-24.
Course Schedule
This section will be updated after class to list the material that was covered along with the lecture notes. Suggested reading that relates to the material covered in class will also be posted. For a tentative schedule of the course, see the syllabus.
- Week 1
- September 7th, 2023:
- Introduction, topological spaces, bases, interiors, closures, limit points
- Munkres 12, 13, 17 (ignore Hausdorff discussion)
- Lecture 1 notes
- September 7th, 2023:
- Week 2
- September 12th, 2023:
- Metric spaces, subspaces, product spaces, quotient spaces.
- Munkres 15, 16, 19, 20, 21. Munkres 3 covers equivalence relations.
- Lecture 2 notes
- September 14th, 2023:
- Continuity.
- Munkres 18.
- Lecture 3 notes
- September 12th, 2023:
- Week 3
- September 19th, 2023:
- Limits and continuity, (path)-connectedness.
- Munkres 23, 24.
- Lecture 4 notes
- September 21th, 2023:
- (Path)-components, compactness
- Munkres 25, 26, 28.
- Lecture 5 notes
- September 19th, 2023:
- Week 4
- September 26th, 2023:
- Compactness, Hausdorff space.
- Munkres 17 (the subsection on Hausdorff spaces), 26, 28.
- Lecture 6 notes
- September 28th, 2023:
- Normal spaces, Urysohn's lemma
- Munkres 30, 31, 32, 33.
- Lecture 7 notes
- September 26th, 2023:
- Week 5
- October 3rd, 2023:
- Urysohn's lemma, Urysohn's metrization theorem, review.
- Munkres 34, 35.
- Lecture 8 notes
- October 5th, 2023:
- In-class exam - Midterm 1
- October 3rd, 2023:
- Week 6
- October 10th, 2023:
- No class
- October 12th, 2023:
- Manifolds, paracompactness.
- Munkres 36, 39, 41.
- Lecture 9 notes
- October 10th, 2023:
- Week 7
- October 17th, 2023:
- Manifolds, paracompactness, covering dimension.
- Munkres 36, 39, 41, 50
- Lecture 10 notes
- October 17th, 2023:
- More covering dimension, Baire's theorem, embeddings of compact metric spaces.
- Munkres 48, 50
- Lecture 11 notes
- October 17th, 2023:
- Week 8
- October 24th, 2023:
- Finished embedding theorem, homotopy.
- Hatcher chapter 0
- Lecture 12 notes
- October 26th, 2023:
- CW-complexes.
- Hatcher chapter 0
- Lecture 13 notes
- October 24th, 2023:
- Week 9
- October 31st, 2023:
- Groups
- Artin chapter 2
- Lecture 14 notes
- November 2nd, 2023:
- More groups, definition of fundamental group
- Artin chapter 2, Hatcher section 1.1
- Lecture 15 notes
- October 31st, 2023:
- Week 10
- November 7th, 2023:
- Fundamental groups, change-of-basepoint, induced homomorphisms
- Hatcher section 1.1
- Lecture 16 notes
- November 9th, 2023:
- Fundamental group of the circle
- Hatcher section 1.1
- Lecture 17 notes
- November 7th, 2023:
- Week 11
- November 14th, 2023:
- In-class exam - Midterm 2
- November 16th, 2023:
- The fundamental theorem of algebra, free groups
- Hatcher section 1.1, 1.2
- Lecture 18 notes
- November 14th, 2023:
- Week 12
- November 21st, 2023:
- The van Kampken Theorem
- Hatcher section 1.2
- Lecture 19 notes
- November 23rd, 2023:
- No class
- November 21st, 2023:
- Week 13
- November 28th, 2023:
- Applications of van Kampen
- Hatcher section 1.2
- Lecture 20 notes
- November 30th, 2023:
- Covering spaces, homotopy lifting
- Hatcher section 1.3
- Lecture 21 notes
- November 28th, 2023:
- Week 14
- December 5th, 2023:
- Covering spaces, classification theorem
- Hatcher section 1.3
- Lecture 22 notes
- December 7th, 2023:
- Covering spaces, universal covers
- Hatcher section 1.3
- Lecture 23 notes
- December 5th, 2023:
- Week 15
- December 12th, 2023:
- Wrapping-up
- Hatcher section 1.3
- Lecture 24 notes
- December 12th, 2023: