Lecture 13

Ch 3, sec 2, and Ch 2, sec 7.

Define the product and weak product of groups. Discuss its "universal property" of the weak product (direct sum) of Abelian groups. At least state Theorem 7.1 of chaper 2, which says that the fundamental group of a product is the product of fundemental groups - and if there is time, prove it. Explain how this allows us to compute the fundamental group of the torus.