A characterization of tame Hilbert-symbol equivalence
Let be a Galois extension with Galois group . We study the set of -linear combinations of characters in the Burnside ring which give rise to -linear combinations of trace forms of subextensions of which are trivial in the Witt ring W of . In particular, we prove that the torsion subgroup of coincides with the kernel of the total signature homomorphism.
We construct an uncountable set of strong automorphisms of the Witt ring of a global field.