Notes: from dual canonical bases to triangular bases of quantum cluster algebras

Abstract: These notes are mainly based on arXiv:2003.13674 and a series of talks given in the workshop CARTEA. For any symmetrizable Kac-Moody algebra $\mathfrak{g}$ and any Weyl group element $w$, the corresponding quantum unipotent subgroup $A_{q}[N_{-}(w)]$ possesses the dual canonical basis $\mathbf{B}^*$. We show that the dual canonical basis is the (common) triangular basis of the quantum cluster algebra. Consequently, we deduce that the basis contains all quantum cluster monomials, extending previous results by the author and Kang-Kashiwara-Kim-Oh.