Xu's polynomial-time conjecture for the maximum forcing number of elementary polyominoes

Let $G$ be an elementary polyomino, meaning a polyomino whose associated plane bipartite graph is elementary. The maximum forcing number conjecture. The maximum forcing number of $G$ can be computed in polynomial time.

This conjecture extends the polynomial-time result known for elementary hexagonal systems to elementary polyominoes. The paper's abstract indicates that it proves the claim, showing that the maximum forcing number of an elementary polyomino equals its Clar number and can therefore be computed in polynomial time.