Bruno Kahn: Un invariant de degré 3 des algèbres centrales simples d'exposant 2

kahn@math.jussieu.fr

Submission: 2009, Nov 5, revised: 2009, Nov 13

We associate to any central simple algebra \$A\$ of exponent \$2\$ over a field of characteristic \$\ne 2\$ an invariant with values in the degree \$2\$ unramified cohomology of its Severi-Brauer variety modulo the image of the cohomology of the ground field. The main theorem is that this invariant is nonzero if and only if the index of \$A\$ is \$\ge 8\$.

2000 Mathematics Subject Classification:

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