Which of the following statements are True, and which are False?

Which of the following statements are True, and which are False?
Give reasons for your answers.

  1. There is a finite field of order 45.
  2. A group G of order 9 has a representation of order 2.
  3. Every free abelian group is a free group
  4. Every set is a semi-group.
  5. If G is an infinite group acting on an infinite set X, then no element of X has finite stabiliser.

Answer:

(5) FALSE: Let {Z} act on itself by translations: i.e if x is an integer , define

image