J. Hausen et P. Schultz, THE MAXIMAL NORMAL P-SUBGROUP OF THE AUTOMORPHISM GROUP OF AN ABELIANP-GROUP, Proceedings of the American Mathematical Society, 126(9), 1998, pp. 2525-2533
Let p be a prime number and let G be an abelian p-group. Let Delta be
the maximal normal p-subgroup of Aut G and zeta the maximal p-subgroup
of its centre. Let t be the torsion radical of epsilon(G). Then Delta
= (1 + t)zeta. The result is new for p = 2 and 3, and the proof is ne
w and valid for all primes p.