Recent content by TheoryNoob

Thanks for the help. Your last post has given me the confidence that my answer is correct and helped clarify my understanding of the theorem.

Thanks for the help. The proof seemed to simple so I had to ask, but now that I realize all the real work for the proof is in the previous theorem it makes sense to be so short.

I'm sorry I should have included this in part 2 of the outline. I am basing this proof of the following theorem: Suppose G is a group and H is a nonempty subset of G. Then H is a subgroup of G iff a,b ∈ H implies ab^-1 ∈ H. We have previously proved this theorem which is why I didn't mention...

Homework Statement Suppose H and K are subgroups of G. Prove H intersect K is a subgroup of G. Homework Equations Suppose G is a group and H is a nonempty subset of G. Then H is a subgroup of G iff a,b ∈ H implies ab^-1 ∈ H. The Attempt at a Solution Suppose a and b elements of H intersect...