2 problems

Let $H$ be the free abelian group of rank $n$, let $\mathcal{L}_n$ be the free Lie algebra generated by $H$, and let $\operatorname{Der}^+(\mathcal{L}_n)$ be its positively graded…

Let $\mathfrak{d}$ be the depth-graded Lie algebra embedded in the $B$-graded Lie algebra of derivations of the free Lie algebra $\mathbb L(a,b)$ preserving $\Theta$, and let…