Star transposition Gray codes for multiset permutations

Petr Gregor, Arturo Merino, Torsten Mütze

Given integers $k\ge 2$ and $a_1,\dots ,a_k\ge 1$, let $\mathbf{a}:=(a_1,\dots ,a_k)$ and $n:=a_1+\cdots +a_k$. An $\mathbf{a}$-multiset permutation is a string of length…