Jan 30

Title: Infiniteness of 4-dimensional mapping class groups and characteristic classes

Speaker: Hokuto Konno (University of Tokyo/MIT)

Abstract: Many authors discovered special phenomena in dimension 4 that do not occur in other dimensions, but today it has become difficult to find such phenomena in classical problems about exotic structures on manifolds. We present a new special phenomenon in dimension 4 from the point of view of infiniteness of mapping class groups and characteristic classes of fiber bundles. The proof uses a new series of characteristic classes obtained from Seiberg-Witten theory for families.