Sandwiches Missing Two Ingredients of Order Four

José D. Alvarado, Simone Dantas, Dieter Rautenbach

For a set $\mathcal{F}$ of graphs, an instance of the $\mathcal{F}$-{\sc free Sandwich Problem} is a pair $(G_1,G_2)$ consisting of two graphs $G_1$ and $G_2$ with the same vertex set su…