 
Summary: J. ALGEBRAIC GEOMETRY
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CHARACTERISTIC ELEMENTS FOR pTORSION
IWASAWA MODULES
KONSTANTIN ARDAKOV AND SIMON WADSLEY
Abstract
Let G be a compact p adic analytic group with no elements of order p.
We provide a formula for the characteristic element [3] of any nitely
generated p torsion module M over the Iwasawa algebra G of G in
terms of twisted invariants of M , which are dened using the Euler
characteristics of M and its twists. A version of the Artin formalism is
proved for these characteristic elements. We characterize those groups
having the property that every nitely generated pseudonull p torsion
module has trivial characteristic element as the p nilpotent groups. It
is also shown that these are precisely the groups which have the property
that every nitely generated p torsion module has integral Euler char
acteristic. Under a slightly weaker condition on G we decompose the
completed group
algebra
