The Johnson homomorphism and the third rational cohomology group of the Torelli group

Abstract

To study the structure of the Torelli group, the Johnson homomorphism and the representation theory of the symplectic group are essential tools. Using them, we give a lower bound for the dimension of the third rational cohomology group and a new approach to the non-triviality of characteristic classes of surface bundles on the Torelli group.

Cite this paper

@inproceedings{Sakasai2003TheJH, title={The Johnson homomorphism and the third rational cohomology group of the Torelli group}, author={Takuya Sakasai and Shigeyuki Morita}, year={2003} }