Signed tilings by ribbon L n-ominoes, n even, via Groebner bases

Kenneth Gill, Viorel Nitica

Let ${\mathcal{T}}_n$ be the set of ribbon $L$-shaped $n$-ominoes for some $n\ge 4$ even, and let ${\mathcal{T}}_n^{+}$ be ${\mathcal{T}}_n$ with an extra $2\times 2$ square. We investigat…