2 problems

Feigin's conjecture. The map $\Phi(i_1,\ldots,i_N)$ is an embedding, and, for at least one special reduced decomposition of $w_0$, it extends to an isomorphism

Let $a$ be a weak composition, let $\mathbb S(a)$ be the associated skew diagram, and let ${\mathfrak K}_{\mathbb S(a)}$ be its skew polynomial. The skew-polynomial expansion conje…