Abstract Algebra: Theory and Applications · Problem 15.4.5

Rings — Thomas Judson

Mathematics — Abstract Algebra · sylow-theorems

Problem

Prove that no group of order 96 is simple. Hint. Since ∣G∣=96=25⋅3|G| = 96 = 2^5 \cdot 3, GG has either one or three Sylow 2-subgroups by the Third Sylow Theorem. If there is only one subgroup, we are done. If there are three Sylow 2-subgroups, let HH and KK be two of them. Therefore, ∣H∩K∣≥16|H \cap K| \geq 16; otherwise, HKHK would have (32⋅32)/8=128(32 \cdot 32)/8 = 128 elements, which is impossible. Thus, H∩KH \cap K is normal in both HH and KK since it has index 2 in both groups.

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