On the degree-two part of the associated graded of the lower central series of the Torelli group

Quentin Faes, Gwenael Massuyeau, Masatoshi Sato

We consider the associated graded ${⨁}_{k\ge 1}{\Gamma }_k\mathcal{I}/{\Gamma }_{k+1}\mathcal{I}$ of the lower central series $\mathcal{I} = Γ_1 \mathcal{I} \supset Γ_2 \mathcal{I} \s…