In this paper we present optimal algorithms to compute monotone stabbers for convex polygons. More precisely, given a set of m convex polygons with n vertices in total we want to stab the polygons with an x-monotone polygonal chain such that each polygon is entered at its leftmost point and departed at its rightmost point. Since such a stabber does not exist in general, we study two related pro...

The stable set polytope of a graph G, denoted as STAB(G), is the convex hull of all the incidence vectors of stable sets of G. To describe a linear system which defines STAB(G) seems to be a difficult task in the general case. In this paper we present a complete description of the stable set polytope of (P6,triangle)-free graphs (and more generally of (P6,paw)-free graphs). For that we combine ...

Group activity recognition is a central theme in many domains, such as sports video analysis, CCTV surveillance, tactics, and social scenario understanding. However, there are still challenges embedding actors’ relations multi-person due to occlusion, movement, light. Current studies mainly focus on collective individual local features from the spatial temporal perspectives, which results ineff...