Summary: #­INVARIANT IDEALS IN IWASAWA ALGEBRAS
K. ARDAKOV, S. J. WADSLEY
Abstract. Let kG be the completed group algebra of a uniform pro­p group
G with coe#cients in a field k of characteristic p. We study right ideals I in
kG that are invariant under the action of another uniform pro­p group #. We
prove that if I is non­zero then an irreducible component of the characteristic
support of kG/I must be contained in a certain finite union of rational linear
subspaces of Spec gr kG. The minimal codimension of these subspaces gives a
lower bound on the homological height of I in terms of the action of a certain
Lie algebra on G/G p . If we take # to be G acting on itself by conjugation,
then #­invariant right ideals of kG are precisely the two­sided ideals of kG, and
we obtain a non­trivial lower bound on the homological height of a possible
non­zero two­sided ideal. For example, when G is open in SLn (Zp ) this lower
bound equals 2n - 2. This gives a significant improvement of the results of
Ardakov, Wei and Zhang [AWZ1] on reflexive ideals in Iwasawa algebras.
1. Introduction
1.1. Prime ideals in Iwasawa algebras. In recent years, several attempts have
been made to understand the structure of prime ideals in non­commutative Iwasawa
algebras. These are the completed group
algebras# G of compact p­adic analytic

Source: Ardakov, Konstantin - School of Mathematical Sciences, University of Nottingham

Collections: Mathematics