# Math 113 Section 1, Summer 2009

Lectures: MTWTh 12-2 in 110 Barker
Office Hours: W 2-3:30, Th 9:30-11
Syllabus: here.
Book: Abstract Algebra: Theory and Applications, by Tom Judson

Suggested reading for Monday, June 22nd: Judson Ch. 0.
Replacement for Chapter 11 - Updated Monday, July 20th, 6 PM.

## Corrections to the Text

-On p. 93, the proof of Cor 5.10 is incomplete: Theorem 5.9 shows that any two cycles of the same length are conjugate by an element of S_n, but the proof of Cor 5.10 assumes that this can be done by an element of A_n, which requires proof. We gave a different proof of Cor 5.10 by showing that if G is a group and H is a subgroup of index 2, then H contains all squares in G, and then noting that all 3-cycles are squares of 3-cycles.
-On p. 140, the proof of Theorem 8.1(1) is incorrect: the fact that the inverse of an isomorphism is a bijection is trivial, but one must check that the inverse of an isomorphism is actually a homomorphism.
-On p. 268, the statement of Eisenstein's criterion given does not follow from the version of the Gauss Lemma given. We fixed this in class by giving a better version of the Gauss Lemma.

## Homework

Homework 1, due Monday, June 29th.
Solutions to Homework 1
Homework 2, due Monday, July 6th.
Solutions to Homework 2
Homework 3, due Monday, July 13th.
Solutions to Homework 3
Homework 4 (Full Version!), due Monday, July 20th.
Solutions to Homework 4
Homework 5, due Monday, July 27th.
Solutions to Homework 5
Homework 6, due Monday, August 3rd.
Solutions to Homework 6
Homework 7, due Monday, August 10th.
Solutions to Homework 7

## Project

Project Guidelines and Deadlines - Note topic choices are due Friday, July 31st.

## Goodies

Cheat Sheet to Proofs about Sets - Updated Thursday, June 25th, 2009.