Arrangements of hypersurfaces and Bestvina-Brady groups

We show that quasi-projective Bestvina-Brady groups are fundamental groups of complements to hyperplane arrangements. Furthermore we relate other normal subgroups of right-angled Artin groups to complements to arrangements of hypersurfaces. We thus obtain examples of hypersurface complements whose fundamental groups satisfy various finiteness properties.Comment: 21 page

Essential coordinate components of characteristic varieties

In this note we give an algebraic and topological interpretation of essential coordinate components of characteristic varieties and illustrate their importance with an example.Comment: 15 pages, 4 postscript figures, to appear in Mathematical Proceedings of the Cambridge Philosophical Societ