No common composition factor with quotient group not implies complemented
This article gives the statement and possibly, proof, of a non-implication relation between two subgroup properties. That is, it states that every subgroup satisfying the first subgroup property (i.e., normal subgroup having no common composition factor with its quotient group) need not satisfy the second subgroup property (i.e., complemented normal subgroup)
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Statement
It is possible to have a finite group having a normal subgroup such that and have no common composition factors, but is not a permutably complemented subgroup of .
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Proof
Further information: special linear group:SL(2,5)
Let , the special linear group of matrices over the field of five elements. Let . Then, is a subgroup of order two and is isomorphic to the alternating group of degree five, which is simple. Thus, and have no common composition factors. However, has no complement in .