学术报告（彦文娇 10.18）

In the isoparametric foliation in the unit sphere, the OT FKM type plays an important role. The focal submanifold M+ of OT-FKM type is a sphere bundle over spheres, including the Stiefel amnifolds as special cases. We construct the characteristic maps corresponding to vector bundle of M+ for m=4 and 8,generalizing the results of Steenrod and James. As an application, we  establish new harmonic representatives of certain elements in homotopy groups of spheres. Moreover, inspired by the OT-FKM construction, we give partial answers to two questions of James.