2 problems

Let $\mathcal T_n$ be the degree-$n$ tree group associated to homology cylinders, and let $\eta'_n\colon\mathcal T_n\to {\sf D}'_n$ be Levine's homomorphism. The preceding theorem…

Let ${\sf L}'_n$ be the degree-$n$ quasi-Lie algebra on generators $X_1,\ldots,X_m$, and let ${\sf D}'_n$ be the kernel of the bracketing map … Let $\mathcal T_n$ be the degree-$n$…