Resumen de R-trees and laminations for free groups II: the dual lamination of an R-tree

Thierry Coulbois, Arnaud Hilion, Martin Lustig

• We define a dual lamination for any isometric very small FN-action on an -tree T. We obtain an Out (FN)-equivariant map from the boundary of the outer space to the space of laminations. This map generalizes the corresponding basic construction for surfaces. It fails to be continuous. We then focus on the case where the tree T has dense orbits. In this case, we give two other equivalent constructions, but of different nature, of the dual lamination