TY - JOUR
T1 - Generic and maximal Jordan types
AU - Friedlander, Eric M.
AU - Pevtsova, Julia
AU - Suslin, Andrei
PY - 2007/6
Y1 - 2007/6
N2 - For a finite group scheme G over a field k of characteristic p>0, we associate new invariants to a finite dimensional kG-module M. Namely, for each generic point of the projectivized cohomological variety Proj Ḣ(G,k)we exhibit a "generic Jordan type" of M. In the very special case in which G=E is an elementary abelian p-group, our construction specializes to the non-trivial observation that the Jordan type obtained by restricting M via a generic cyclic shifted subgroup does not depend upon a choice of generators for E. Furthermore, we construct the non-maximal support variety Γ(G) M , a closed subset of Proj Ḣ (G,k) which is proper even when the dimension of M is not divisible by p.
AB - For a finite group scheme G over a field k of characteristic p>0, we associate new invariants to a finite dimensional kG-module M. Namely, for each generic point of the projectivized cohomological variety Proj Ḣ(G,k)we exhibit a "generic Jordan type" of M. In the very special case in which G=E is an elementary abelian p-group, our construction specializes to the non-trivial observation that the Jordan type obtained by restricting M via a generic cyclic shifted subgroup does not depend upon a choice of generators for E. Furthermore, we construct the non-maximal support variety Γ(G) M , a closed subset of Proj Ḣ (G,k) which is proper even when the dimension of M is not divisible by p.
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U2 - 10.1007/s00222-007-0037-2
DO - 10.1007/s00222-007-0037-2
M3 - Article
AN - SCOPUS:34247489729
SN - 0020-9910
VL - 168
SP - 485
EP - 522
JO - Inventiones Mathematicae
JF - Inventiones Mathematicae
IS - 3
ER -