Math 31 Homework #22

Mathematicians are like lovers...
grant a mathematician the least principle, and he will draw from it a consequence,
which you must also grant him, and from this consequence another...
Fontenelle

Reading

Read what we will cover in class on 2/24: Chapter 12

When reading Chapter 12 pay special attention to the following concepts:

  • ring, examples and nonexamples, properties of multiplications, uniqueness of the unity and inverses, subring and the subring test.

Problems

The following problems are due by the beginning of class on Wednesday 2/24.
  • Ch 29 : 3, 4, 5, 11, 12.
  • Prove that if G is a group of permutations on a set S and s,t from S are in the same orbit under G, then orbG(s) = orbG(t).
  • For 3,4,5 are asking you to consider "necklaces" as opposed to "tiles."
  • The answer for 4 is 92.
  • For 11, 12, you just need to show that the given map g -> \phig is a homomorphism; this is the definition of a group action.