Semester page for MAT4200 - Autumn 2026

Next Tuesday’s lecture will be postponed to the following week and will take place on Friday the 13th from 12-14 in Room NHA 1120

Wednesday the 4th, Jules Chenal will cover integral dependence in a one off lecture. You’re welcome to contact me by email if you have any questions while I am away. 

There was an error in Problem 5 of the Obligatory assignment, the statement you were asked to prove in Part 1 is false in general without the additional assumption that the ring R be an integral domain. The problem set has now been updated in the .tex and .pdf files on the site. 

Thanks to Jan Meeus for pointing out the error. I apologise for the mistake. 

This exercise was an adaptation of Exercises 12 and 13 of Chapter 3 of Atiyah-Macdonald where the integral domain assumption was made at the beginning. It might be helpful to take a look at these exercises to get more intuition about torsion and torsion freeness. In particular Exercise 12 Part iii provides one route to prove the statement in part one. 

Do not hesitate to get in touch if you would like more hints or help with this or other problems.

There’s a slight change in the office hour time for today. We’ll start 15 minutes later than announced on Wednesday.

The PDF and .tex files for the assignment can be found here (it was posted Wednesday but the messaging system was down):

https://www.uio.no/studier/emner/matnat/math/MAT4200/h26/Obligatory%20assignment/

The assignment is due in canvas on the 22nd of October at 14:30.I will have office hours on Friday the 9th from 13:00-14:00 and Tuesday from 15:00-16:00 in NHA 1116.

Tomorrow's lecture will be held from 15:15 to 17:00 (shifted by one hour).