6 papers
Strong invariants and Tverberg numbers in convexity spaces
Minho Cho, Andreas F. Holmsen, Attila Jung +1
Helly, Carathéodory, and Radon numbers encode three kinds of finite certificates in a convexity space: for the emptiness of an intersection, for membership in a convex hull, and f…
Intersection patterns in spaces with a forbidden homological minor
Xavier Goaoc, Andreas F. Holmsen, Zuzana Patáková
In this paper we study generalizations of classical results on intersection patterns of set systems in , such as the fractional Helly theorem or the -theorem,…
Piercing all maximum cliques in hypergraphs
Andreas Holmsen, Attila Jung, Balázs Keszegh +5
Graphs whose maximum clique size exceeds half of the total number of vertices satisfy a classical property: the family of their maximum sized cliques can be pierced by a single ver…
The fractional Helly number for separable convexity spaces
Andreas F. Holmsen, Zuzana Patáková
A convex lattice set in is the intersection of a convex set in with the integer lattice . A classical theorem of Doignon states that the…
Helly type problems in convexity spaces
Andreas F. Holmsen
We report on some recent progress regarding combinatorial properties in convexity spaces with a bounded Radon number. In particular, we discuss the relationship between the Radon n…
A topological product Tverberg Theorem
Andreas F. Holmsen, Grace McCourt, Daniel McGinnis +1
We prove a generalization of the topological Tverberg theorem. One special instance of our general theorem is the following: Let denote the 8-dimensional simplex viewed as an…