Homepage for MATH 250A (Fall 2001)

Lectures

... are conducted weekly on Tuesdays and Thursdays (2:00 - 3:30pm), in room 70 Evans. The professor who's teaching this course in Ken Ribet, you should check his homepage regularly for updates. PS. In case you haven't realized, I'm the GSI for this course.

Office Hours

There have been some slight changes in my office hours (in 816 Evans):
Monday12 noon - 1 pm
Wednesday11 am - 12 noon
Thursday3:30 pm - 4:30 pm


Homework
  1. Homework is due on every Tuesday, during the lecture. Check out the problems at Ken's Math 250 homepage.
  2. Note that shortly after the lecture, the solutions will be available on the web. Hence, under no circumstances will late homework be accepted. A professor I know used to say "instead of handing in your homework one hour late, just start one hour earlier." Ok, I know people don't work that way (at least I don't), but learn to meet the deadline, and everyone will be happy.
    (Latest update 11 Sep 2001: Seems like there were students who're living in San Francisco and unable to get to school because of today's events. Due to exceptional circumstances, deadline for homework 2 has been extended to 12 Sep.)

  3. Comments about the homework:
    Homework 1 (due 4 Sep 2001, graded 12 Sep 2001).
    Homework 2 (due 12 Sep 2001, graded 18 Sep 2001).
    Homework 3 (due 18 Sep 2001, graded 24 Sep 2001).
    Homework 4 (due 25 Sep 2001, graded 4 Oct 2001).
    Homework 5 (due 4 Oct 2001, graded 15 Oct 2001).
    Homework 6 (due 11 Oct 2001, graded 25 Oct 2001).
    Homework 7 (due 18 Oct 2001, graded 30 Oct 2001 as promised).
    Homework 8 (due 25 Oct 2001, graded 28 Nov 2001).
    Homework 9
    Homeworks 10 & 11
Note that the future grading dates are merely estimated.


Extra Problems

Occasionally, I may add some problems here and there, which may be of interest to some students. Note that these aren't homework problems, and nothing is gained by submitting your solutions, except perhaps a boosted ego.
  1. If K is a normal subgroup of H and H is a normal subgroup of G, must K be a normal subgroup of G?
  2. Let G be a finite group whose order is not a multiple of 3. If x3y3 = (xy) 3 for all x, y in G, prove that G is abelian.
  3. Construct a group G and a normal subgroup H such that H and G/H are both isomorphic to Z but G is not isomorphic to Z2.
  4. Related to "Egyptian fractions" in homework 2, prove that every positive integer n can be expressed as the sum of distinct fractions of the form 1/m. E.g. 2 = 1/1 + 1/2 + 1/3 + 1/6 etc.


Stay tuned while I update this homepage from time to time. You can throw an email to me at limchuwe@math.berkeley.edu.

This page was last updated on 7 Dec 2001.