Let $G$ be a finite group such that $G/Z(G)\cong K_4$ (Klien's 4 group).
$G/G'$ and $Z(G)$ both have exponent $4$, then $G$ can be written as direct product of $A$ times $H$ where $A$ is an abelian group and $H$ cannot be written as such a direct product as G is written means H is indecomposable. In other words we can say that H behaves similar to G means same properties as that of G but how to prove that G can be written in such a way?
http://math.stackexchange.com/questions/908033/uniqueness-of-the-direct-product-decomposition-of-finite-groups
– verret Jan 12 '16 at 05:52