2 problems

Berenstein–Kazhdan's presentation conjecture. The algebra ${\bf D}(W)$ is generated by the $D_s$ subject to the idempotent relations $D_s^2=D_s$, the braid relations

Let $A=(a_{ij})$, $i,j\in I$, be a generalized Cartan matrix, and let $W=W_A$ be the corresponding crystallographic Coxeter group, with … for $i\ne j$. Let…