Let G be a group, and let H = {(g, g)
Chapter 8, Problem 27E(choose chapter or problem)
Problem 27ELet G be a group, and let H = {(g, g) | g∈G}. Show that H is a subgroup of G ⊕ G. (This subgroup is called the diagonal of G ⊕ G.) When G is the set of real numbers under addition, describe G ⊕ G and H geometrically.
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