Thomas Delzant: Kähler groups, deficiency and the geometric invariant

Kähler groups are, by definition, groups that can be realized as fundamental groups of Kähler manifolds (for instance smooth complex projective). The deficiency of a presentation of a group is the difference between number of generators and the number of relations. In this lecture, we will apply the so called "BNS" theory to study Kähler groups with positive deficiency. This is joint work with R. Strebel.