New series in the Johnson cokernels of the mapping class groups of surfaces

Abstract

In the present paper, we study the Sp-module structure of the cokernel of the Johnson homomorphism of the mapping class groups of surfaces. We detect the Sp-irreducible components with highest weight [1^k] (and [k]) in the cokernel. We also show that the multiplicities of them is equal to one.

40 pages. In our previous version, the conjecture 7.8 is not true. In the revised version, we added some problems and discussions for our series in the Johnson cokernels. We correct a link to our preprint in the reference [Sa]