Partially compactified quantum cluster structures on simple algebraic groups and the full Berenstein--Zelevinsky conjecture

The construction of partially compactified cluster algebras on coordinate rings is handled by using codimension 2 arguments on cluster covers. An analog of this in the quantum situation is highly desirable but has not been found yet. In this paper, we present a general method for the construction of partially compactified quantum cluster algebra structures on quantized coordinate rings from that of quantum cluster algebra structures on localizations. As an application, we construct a partially compactified quantum cluster algebra structure on the quantized coordinate ring of every connected, simply connected complex simple algebraic group. Along the way, we settle in full the Berenstein--Zelevinsky conjecture that all quantum double Bruhat cells have quantum cluster algebra structures associated to seeds indexed by arbitrary signed words, and prove that all such seeds are linked to each by mutations.