On Relative Grothendieck Rings
نویسنده
چکیده
Let K be a field of characteristic pi^O, to exclude trivial cases) and let G be a finite goup. A XG-module M is a finite dimensional K-vector space, on which G acts Jf-linearly from the left. The Green ring a(G) of G(w.r.t. K) is the free abelian group, spanned by the isomorphism classes of indecomposable i£G-modules, with the multiplication induced from the tensor product © x of KGmodules (see [4]). If U^G one has a restriction map a(G)—*a(U), induced from restricting the action of G on a 2£G-module M to U, thus getting &KUmodule M\ u. Let U be a family of subgroups of G. An exact sequence
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تاریخ انتشار 2007