24 citations · 94 across the 38 of their papers we have counts for
4 papers · 1 filter
Orienting triangulations
Boris Albar, Daniel Gonçalves, Kolja Knauer
We prove that any triangulation of a surface different from the sphere and the projective plane admits an orientation without sinks such that every vertex has outdegree divisible b…
How many circuits determine an oriented matroid?
Kolja Knauer, Luis Pedro Montejano, Jorge Luis Ramírez Alfonsín
Las Vergnas and Hamidoune studied the number of circuits needed to determine an oriented matroid. In this paper we investigate this problem and some new variants, as well as their…
Intersection Graphs of L-Shapes and Segments in the Plane
Stefan Felsner, Kolja Knauer, George B. Mertzios +1
An L-shape is the union of a horizontal and a vertical segment with a common endpoint. These come in four rotations: L, Γ, LE{} and \eeG. A -bend path is a simple path in the pl…
On the Duality of Semiantichains and Unichain Coverings
Bartłomiej Bosek, Stefan Felsner, Kolja Knauer +1
We study a min-max relation conjectured by Saks and West: For any two posets and the size of a maximum semiantichain and the size of a minimum unichain covering in the prod…