TITLE: Is there an analogue of the hive model for Littlewood-Richardson coefficients of types $B$, $C$ and $D$?
QUESTION [19 upvotes]: If $V_\lambda$, $V_\mu$ and $V_\nu$ are irreducible representations of $\operatorname{GL}_n$, the Littlewood-Richardson coefficient $c_{\lambda\mu}^\nu$ denotes the multiplicity of  $V_\nu$ in the direct sum decomposition of the tensor product of $V_\lambda$ and $V_\nu$.
Knutson and Tao (JAMS 1999, link at AMS site) proposed a  "hive model" for Littlewood-Richardson coefficients.
Is there an analogous model for such tensor product multiplicities for Lie groups of types B, C or D?

REPLY [6 votes]: There is some recent progress on this question.  JiaRui Fei https://arxiv.org/pdf/1603.02521.pdf has given a generalization of the hive model for all semisimple Lie algebras, based on the theory of cluster algebras.  In type A, his model specializes to the Knutson-Tao hive model.