منابع مشابه
Galois Module Structure of Galois Cohomology
Let F be a field containing a primitive pth root of unity, and let U be an open normal subgroup of index p of the absolute Galois group GF of F . We determine the structure of the cohomology group H(U, Fp) as an Fp[GF /U ]-module for all n ∈ N. Previously this structure was known only for n = 1, and until recently the structure even of H(U, Fp) was determined only for F a local field, a case se...
متن کاملÉtale cohomology and Galois Representations
In this essay we briefly introduce the main ideas behind the theory of studying algebraic varieties over a number field by constructing associated Galois representations, and see how this can be understood naturally in the context of an extension of monodromy theory from geometry. We then, following Deligne’s original method, use some of these ideas to prove the Riemann Hypothesis for varieties...
متن کاملHopf Galois structures on primitive purely inseparable extensions
Let L/K be a primitive purely inseparable extension of fields of characteristic p, [L : K] > p, p odd. It is well known that L/K is Hopf Galois for some Hopf algebra H, and it is suspected that L/K is Hopf Galois for numerous choices of H. We construct a family of K-Hopf algebras H for which L is an H-Galois object. For some choices of K we will exhibit an infinite number of such H. We provide ...
متن کامل5 Some additive galois cohomology rings
Let p ≥ 3 be a prime. We consider the cyclotomic extension Z (p) [ζ p 2 ] | Z (p) , with galois group G = (Z/p 2) *. Since this extension is wildly ramified, the Z (p) G-module Z (p) [ζ p 2 ] is not projective. We calculate its cohomology ring H * (G, Z (p) [ζ p 2 ]; Z (p)), carrying the cup product induced by the ring structure of Z (p) [ζ p 2 ]. Formulated in a somewhat greater generality, ou...
متن کاملSome cyclotomic additive Galois cohomology rings
Let p ≥ 3 be a prime. We consider the cyclotomic extension Z(p)[ζp2] of Z(p), with Galois group G := (Z/p2)∗. Since this extension is wildly ramified, Z(p)[ζp2] is not projective as a module over the group ring Z(p)G (Speiser). Extending this module structure, we can regard Z(p)[ζp2 ] as a module over the twisted group ring Z(p)[ζp2] ≀G; as such, it remains faithful and non projective. We calcu...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Journal of Algebra
سال: 1976
ISSN: 0021-8693
DOI: 10.1016/0021-8693(76)90227-1