Math 8202 Homework 1

Date due: February 1, 2010

Hand in only the starred questions. One of the other problems may show up on the first quiz on February 8.

If you want me to do in class any of the questions I have given you, do let me know (on or after the due date for the assignment). For instance, if you want me to do on February 1 (8, respectively) or later any of the questions below (not, respectively) assigned to be handed in, please tell me.

Section 3.4: 2, 5, 11*, 12*

Hint to Problem 11: If G were finite, you could use the hint to Problem 8 in the text, i.e., consider a minimal nontrivial normal subgroup A of G contained in H. To do this problem in general, consider the derived series of H, see Section 6.1.

Section 3.5: 3, 4, 7 (rigid motions = rotations), 9*, 10, 17

A. Prove that A4 is the only subgroup of S4 having order 12.

B*. Make a complete list of all possible composition series for S4. Show that there are no more composition series other than the ones you have indicated. [You may use results from other homework questions.]