Algebraic construction of homology and cohomology theories, aimed at applications to topology, geometry, groups and rings. Special emphasis on hom and tensor functors; projective, injective and flat modules; exact sequences; chain complexes; derived functors, in particular, ext and tor.

Prerequisites: Mathematics 220A-B-C.

4

Units

Optional

Grading

1, 2, 3

Passtime

None

Level Limit

Letters and science

College
ZHAO XIAOLEI
Xiaolei Zhao
3.7
12 reviews
AI predicted, based on past grading trends of the course and instructor, class info, and 127 other factors
Spring 2025 . Zhao Xiaolei
ILP 4101
M W F
13:00 PM - 13:50 PM
See All
MATH 236B Zhao Xiaolei Spring 2025 Total: 11
MATH 236B Zhao Xiaolei Spring 2023 Total: 17
See All
12
3.7
math117 . Zhao Xiaolei 1 Year, 8 Months Ago

Straight up just copied out of a textbook. He did not explain proofs well enough that made sense. i'd avoid him. grades on a curve cuz the tests make no sense. or maybe im just stupid...

0 helpful 0 unhelpful
math117 . Zhao Xiaolei 1 Year, 9 Months Ago

Smart and handsome guy. Really into math stuff. But the grading is a bit harsh but luckily he curves the grades finally..

0 helpful 0 unhelpful
math117 . Zhao Xiaolei 2 Years Ago

Don't take him. Final and midterm weight heavy, and the tests are hard. A lots of assignments have to do. 117 is stressful and the lecture is not helpful.

0 helpful 0 unhelpful
147A . Zhao Xiaolei 2 Years Ago

Really helpful lectures, and he's good at answering questions. He didn't assign a ton of homework, but what he did assign was pretty hard so going to office hours was necessary for me. The tests were hard, but he graded and curved SUPER generously. Honestly nothing bad to say, I'd recommend him to anyone.

0 helpful 0 unhelpful
math117 . Zhao Xiaolei 2 Years Ago

He only copy down the textbook on the whiteboard. test are difficult and tough grader, avoid him!!! I don't think he's aware that this is a summer course.

0 helpful 0 unhelpful
MATH111ABC . Zhao Xiaolei 2 Years Ago

midterm/final average was low af. doesnt really teach and expects you to review stuff on your own. tests are difficult

0 helpful 0 unhelpful
See all 12 reviews
MATH 221B
0 / 30 Enrolled
Homotopy Theory
Stephen Bigelow 3.4
T R
12:30 PM - 13:45 PM
MATH 225B
0 / 25 Enrolled
Topics in Number Theory
Zheng Liu 3.8
T R
14:00 PM - 15:15 PM
MATH 227B
0 / 25 Enrolled
Advanced Topics in Geometric and Algebraic Topology
Yuedong Wang 3.4
T R
11:00 AM - 12:15 PM
MATH 240B
0 / 20 Enrolled
Introduction to Differential Geometry and Riemannian Geometry
Gufong Wei 2.3
M W
09:30 AM - 10:45 AM
MATH 241B
0 / 20 Enrolled
Topics in Differential Geometry
Matthias Wink 3.0
M W
12:30 PM - 13:45 PM
MATH 246B
0 / 25 Enrolled
Partial Differential Equations
Bohan Zhou 4.0
T R
14:00 PM - 15:15 PM