Centrioles in symmetric spaces Peter Quast (Augsburg) The notion of a centriole in a symmetric space has been introduced by Chen and Nagano in 1988. Centrioles are natural generalizations of equatorial hyperspheres in spheres to other symmetric spaces of compact type. In the first part of our talk we describe the geometry of centrioles and classify centrioles in simply connected irreducible symmetric spaces of compact type in terms of root systems. The second part of our talk is devoted to applications of centrioles to homotopy. Centrioles play an important role in Bott's original proof of his famous periodicity theorem for the homotopy of classical matrix groups. We disucss a periodicity result for inclusions. The second part of our talk is joint work with A.-L.Mare (University of Regina, Canada).