Rooted quasi-Stirling permutations of general multisets

Shishuo Fu, Yanlin Li

Given a general multiset $\mathcal{M}=\{1^{m_1},2^{m_2},\dots ,n^{m_n}\}$, where $i$ appears $m_i$ times, a multipermutation $\pi$ of $\mathcal{M}$ is called {\em quasi-Stirling}, if…