First Galois cohomology unramified outside a finite set

ID: first-galois-cohomology-unramified-outside-a-finite-set

For a finite Galois module unramified outside a finite set , define as the classes in Galois cohomology whose restriction to inertia is zero at every finite prime outside . This means zero as a cohomology class, rather than zero for every possible representative. Passing to a finite Galois extension on which is constant reduces the finiteness problem to characters with bounded ramification and a finite restriction kernel.

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