Hermitian vector bundles and extension groups

(Un exposé de Klaus Kunnemann au séminaire de théorie des nombres de Chevaleret le 17 novembre 2003)

Résumé :

 
We define arithmetic extension groups, compute these groups in
certain cases and introduce heights of extensions over arithmetic curves.
We investigate classes of natural extensions in arithmetic geometry: The
Hodge and the Atiyah extension.

This is joint work with J. B. Bost.