nu, a list, a partition with |nu| = |lambda| - |mu|
Outputs:
a list, the list of LR fillings of the skew shape lambda/mu with content nu
Description
An LR tableau is a semistandard skew tableau (rows weakly increasing, columns strictly increasing) whose reverse reading word is a lattice word. Each filling is returned as a list of rows; row $i$ has length $\lambda_i - \mu_i$ and entries in $\{0, \ldots, \#\nu - 1\}$ (so label 0 corresponds to row 1 of $\nu$, etc.). The number of LR tableaux equals the Littlewood-Richardson coefficient $c^\lambda_{\mu,\nu}$.