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07/31/2023
Boundedness for proper conflict-free and odd colorings
The proper conflict-free chromatic number, χ_pcf(G), of a graph G is the...
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03/24/2023
Roudneff's Conjecture in Dimension 4
J.-P. Roudneff conjectured in 1991 that every arrangement of n ≥ 2d+1≥ 5...
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03/23/2023
Clustered independence and bounded treewidth
A set S⊆ V of vertices of a graph G is a c-clustered set if it induces a...
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03/15/2023
Concepts of Dimension for Convex Geometries
Let X be a finite set. A family P of subsets of X is called a convex geo...
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02/23/2022
Lattice path matroids and quotients
We characterize the quotients among lattice path matroids (LPMs) in term...
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02/14/2022
Beyond symmetry in generalized Petersen graphs
A graph is a core or unretractive if all its endomorphisms are automorph...
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11/29/2021
Feedback vertex sets in (directed) graphs of bounded degeneracy or treewidth
We study the minimum size f of a feedback vertex set in directed and und...
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10/28/2021
Labeled sample compression schemes for complexes of oriented matroids
We show that the topes of a complex of oriented matroids (abbreviated CO...
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10/03/2021
On monoid graphs
We investigate Cayley graphs of finite semigroups and monoids. First, we...
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02/01/2021
On the dichromatic number of surfaces
In this paper, we give bounds on the dichromatic number χ⃗(Σ) of a surfa...
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09/01/2020
On sensitivity in bipartite Cayley graphs
Huang proved that every set of more than half the vertices of the d-dime...
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07/24/2020
Ample completions of OMs and CUOMs
This paper considers completions of COMs (complexes oriented matroids) t...
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07/15/2020
Plattenbauten: Touching Rectangles in Space
Planar bipartite graphs can be represented as touching graphs of horizon...
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08/06/2019
Enumerating k-arc-connected orientations
We give simple algorithms to enumerate the α-orientations of a graph G i...
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06/14/2019
On the Djoković-Winkler relation and its closure in subdivisions of fullerenes, triangulations, and chordal graphs
It was recently pointed out that certain SiO_2 layer structures and SiO_...
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06/11/2019
Two-dimensional partial cubes
We investigate the structure of two-dimensional partial cubes, i.e., of ...
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02/16/2019
Flip distances between graph orientations
Flip graphs are a ubiquitous class of graphs, which encode relations ind...
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06/12/2018
The queue-number of posets of bounded width or height
Heath and Pemmaraju conjectured that the queue-number of a poset is boun...
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06/12/2018
The queue-number of planar posets
Heath and Pemmaraju conjectured that the queue-number of a poset is boun...
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05/08/2018
The interval number of a planar graph is at most three
The interval number of a graph G is the minimum k such that one can assi...
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12/17/2017
Cuts in matchings of 3-edge-connected cubic graphs
We discuss relations between several known (some false, some open) conje...
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10/09/2017
Computing metric hulls in graphs
We prove that, given a closure function the smallest preimage of a close...
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10/06/2017