Higher limits over the fusion orbit category via centralizers of amalgams

Abstract

We study the D\'iaz-Park sharpness conjecture for fusion systems and prove that, under certain circumstances, there exists a 4 terms exact sequence relating the first two higher limits of the contravariant part of a Mackey functor over certain fusion systems. We show how this result can be applied to the family of Benson-Solomon fusion systems thus providing another approach to studying the sharpness for this family of fusion systems.