The Witt groups of the spheres away from two

For instance, we solve the homotopy limit problem for Dedekind rings whose fraction field is a number field, calculate the various flavours of Grothendieck-Witt groups ofℤ, show

The vanishing of the second cohomology group of the Witt and the Virasoro algebra with val- ues in the adjoint module has been proved by Schlichenmaier in [29, 30] by using

In Section 6, we give the results for the first and second algebraic cohomology of the Witt and the Virasoro algebra with values in the general tensor densities modules, though

• Low-dimensional cohomology: interpretation in terms of invariants, outer derivations, extensions, deformations and obstructions, as well as crossed modules ↔ their knowledge allows

Subsequently, we continue by recalling results known in the case of the zeroth, first and second algebraic cohomology of the Witt and the Virasoro algebra, with values in the

in particular, there is a well defined intersection cohomology signature; – there are well-defined and nontrivial Witt bordism groups ΩWitt T for example, these are

Ce complexe est la généralisation naturelle aux Z (p) -algèbres du complexe de de Rham–Witt pour les F p -algèbres de Bloch–Deligne–Illusie [L. Nous donnons aussi une

In contrast, the case of split spin groups, corre- sponding to invariants of Quad n ∩ I 3 (meaning that the Witt classes of the forms must be in I 3 ), is very much open, and has