5 problems

Gribonval–Hardin–Nielsen conjecture. For unconditional bases, one has

Berasategui–Lassalle conjecture. An $\mathbf s$-semi-greedy Markushevich basis is also semi-greedy.

Let $\mathcal{A}_v(b,c)$ be a rank 2 quantum cluster algebra, let $C[a_1,a_2]$ be a triangular basis element, and write its expansion in the quantum greedy basis as … where…

Let $\mathcal{A}_v(b,c)$ be a rank 2 quantum cluster algebra, and suppose that $b\mid c$ or $c\mid b$. Let $Y\le Z$ mean that $Z-Y$ is a Laurent polynomial with coefficients in…

Democracy characterization conjecture. If