Regularity and the Gorenstein property of L-convex polyominoes

Official URL: http://dx.doi.org/10.37236/9531

We study the coordinate ring of an L-convex polyomino, determine its regularity in terms of the maximal number of rooks that can be placed in the polyomino. We also characterize the Gorenstein L-convex polyominoes and those which are Gorenstein on the punctured spectrum, and compute the Cohen-Macaulay type of any L-convex polyomino in terms of the maximal rectangles covering it. Though the main results are of algebraic nature, all proofs are combinatorial.