Puig subgroup explained

In finite group theory, the Puig subgroup, introduced by, is a characteristic subgroup of a p-group analogous to the Thompson subgroup.

Definition

If H is a subgroup of a group G, then L_G(H) is the subgroup of G generated by the abelian subgroups normalized by H.

The subgroups L_n of G are defined recursively by

• L₀ is the trivial subgroup
• L_n+1 = L_G(L_n)

They have the property that

• L₀ ⊆ L₂ ⊆ L₄... ⊆ ...L₅ ⊆ L₃ ⊆ L₁

The Puig subgroup L(G) is the intersection of the subgroups L_n for n odd, and the subgroup L_*(G) is the union of the subgroups L_n for n even.

Properties

Puig proved that if G is a (solvable) group of odd order, p is a prime, and S is a Sylow p-subgroup of G, and the -core of G is trivial, then the center Z(L(S)) of the Puig subgroup of S is a normal subgroup of G.