Syzygies and diagonal resolutions for dihedral groups
نویسنده
چکیده
Let G be a finite group with integral group ring Λ = Z[G]. The syzygies Ωr(Z) are the stable classes of the intermediate modules in a free Λ-resolution of the trivial module. They are of significance in the cohomology theory of G via the ‘co-represention theorem’ Hr(G,N) = HomDer(Ωr(Z), N). We describe the Ωr(Z) explicitly for the dihedral groups D4n+2, so allowing the construction of free resolutions whose differentials are diagonal matrices over Λ.
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