We study the permutation group $\mathcal{ BK}_P$ generated by Bender-Knuth moves on linear extensions of a poset $P$, an analog of the Berenstein-Kirillov group on column-strict tableaux. We explore the group relations, with an emphasis on identifying posets $P$ for which the cactus relations hold in $\mathcal{ BK}_P$. We also examine $\mathcal{ BK}_P$ as a subgroup of the symmetric group $\mathfrak{ S}_{ \mathcal{ L}(P)}$ on the set of linear extensions of $P$ with the focus on analyzing posets $P$ for which $\mathcal{ BK}_P = \mathfrak{ S}_{ \mathcal{ L}(P)}$.
Categories: math.CO math.RT