Use the Fundamental Theorem of Homomorphism for Groups to prove the following theorem, which is called the Zassenhaus (Butterfly) Lemma:
Let H and K be subgroups of a group G and H′ and K′ be normal subgroups of H
and K, respectively. Then
i) H′(H ∩ K′) H′(H ∩ K)
ii) K′(H′∩ K) K′(H ∩ K)
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