Nielsen realization problem for the mapping class group Mod(Sg)
asks whether the natural projection pg:Homeo+(Sg)→Mod(Sg) has a section. While all the previous results use torsion
elements in an essential way, in this paper, we focus on the much more
difficult problem of realization of torsion-free subgroups of
Mod(Sg). The main result of this paper is that the Torelli group has
no realization inside the area-preserving homeomorphisms.Comment: 22 pages, 5 figure