The boundary of a quasiconvex space

We study the asymptotic geometry of quasiconvex spaces, a class of nonpositively curved metric spaces that includes both Gromov negatively curved and CAT(0)-spaces. In particular, we define the boundary of a quasiconvex space in a way that generalizes the Gromov boundary of a negatively curved space as well as the visual boundary of a CAT(0)-space. This allows us to give a unified treatment of boundaries in these two special settings.