Charles University

output

19922026

most citedObservation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC

10.9k citations

researchers with a paper here

Counting papers with at most 25 authors, so collaboration author lists do not stand in for the people here.

collaborating institutions

Showing 2018 · math.COShow all

15 papers · 2 filters

math.CO2018★ 2 cited

A rainbow version of Mantel's Theorem

Ron Aharoni, Matt DeVos, Sebastián González Hermosillo de la Maza +2

Mantel's Theorem asserts that a simple $n$ vertex graph with more than $\frac{1}{4} n^{2}$ edges has a triangle (three mutually adjacent vertices). Here we consider a rainbow variant…

math.CO2018★ 2 cited

1-subdivisions, fractional chromatic number and Hall ratio

Zdeněk Dvořák, Patrice Ossona de Mendez, Hehui Wu

The Hall ratio of a graph G is the maximum of |V(H)|/alpha(H) over all subgraphs H of G. Clearly, the Hall ratio of a graph is a lower bound for the fractional chromatic number. It…

math.CO2018★ 2 cited

Zeros of the Möbius function of permutations

Robert Brignall, Vít Jelínek, Jan Kynčl +1

We show that if a permutation $π$ contains two intervals of length 2, where one interval is an ascent and the other a descent, then the Möbius function $μ [π]$ of the interval $[1,π…

math.CO2018★ 4 cited

On the growth of the Möbius function of permutations

Vít Jelínek, Ida Kantor, Jan Kynčl +1

We study the values of the Möbius function $μ$ of intervals in the containment poset of permutations. We construct a sequence of permutations $π_{n}$ of size $2 n - 2$ for which $μ(1,π_…

math.CO2018★ 5 cited

Forbidden cycles in metrically homogeneous graphs

Jan Hubička, Michael Kompatscher, Matěj Konečný

In a recent paper by a superset of the authors it was proved that for every primitive 3-constrained space $Γ$ of finite diameter $δ$ from Cherlin's catalogue of metrically homogene…

math.CO2018★ 9 cited

A $4$ -choosable graph that is not $(8 : 2)$ -choosable

Zdeněk Dvořák, Xiaolan Hu, Jean-Sébastien Sereni

In 1980, Erdős, Rubin and Taylor asked whether for all positive integers $a$ , $b$ , and $m$ , every $(a : b)$ -choosable graph is also $(am : bm)$ -choosable. We provide a negative answer…

math.CO2018

(3a:a)-list-colorability of embedded graphs of girth at least five

Zdeněk Dvořák, Xiaolan Hu

A graph G is list (b:a)-colorable if for every assignment of lists of size b to vertices of G, there exists a choice of an a-element subset of the list at each vertex such that the…

math.CO2018★ 12 cited

On difference graphs and the local dimension of posets

Jinha Kim, Ryan R. Martin, Tomáš Masařík +4

The dimension of a partially-ordered set (poset), introduced by Dushnik and Miller (1941), has been studied extensively in the literature. Recently, Ueckerdt (2016) proposed a vari…

math.CO2018

Single-conflict colouring

Zdeněk Dvořák, Louis Esperet, Ross J. Kang +1

Given a multigraph, suppose that each vertex is given a local assignment of $k$ colours to its incident edges. We are interested in whether there is a choice of one local colour pe…

math.CO2018★ 2 cited

The $Z_{2}$ -genus of Kuratowski minors

Radoslav Fulek, Jan Kynčl

A drawing of a graph on a surface is independently even if every pair of nonadjacent edges in the drawing crosses an even number of times. The $Z_{2}$ -genus of a graph $G$ i…

math.CO2018★ 4 cited

Structure and generation of crossing-critical graphs

Zdeněk Dvořák, Petr Hliněný, Bojan Mohar

We study $c$ -crossing-critical graphs, which are the minimal graphs that require at least $c$ edge-crossings when drawn in the plane. For $c = 1$ there are only two such graphs witho…

math.CO2018★ 8 cited

Gray codes and symmetric chains

Petr Gregor, Sven Jäger, Torsten Mütze +2

We consider the problem of constructing a cyclic listing of all bitstrings of length $2 n + 1$ with Hamming weights in the interval $[n + 1 - ℓ, n + ℓ]$ , where $1 \leq ℓ \leq n + 1$ , by…

math.CO2018★ 1 cited

Planar graphs without cycles of length 4 or 5 are (11:3)-colorable

Zdeněk Dvořák, Xiaolan Hu

A graph G is (a:b)-colorable if there exists an assignment of b-element subsets of {1,...,a} to vertices of G such that sets assigned to adjacent vertices are disjoint. We show tha…

math.CO2018★ 1 cited

Algorithmic aspects of $M$ -Lipschitz mappings of graphs

Jan Bok

$M$ -Lipschitz mappings of graphs (or equivalently graph-indexed random walks) are a generalization of standard random walk on $Z$ . For $M \in N$ , an \emph{ $M$ -Lipschitz m…

math.CO2018★ 2 cited

Characterizing subclasses of cover-incomparability graphs by forbidden subposets

Jan Bok, Jana Maxová

In this paper we continue investigations of cover-incomparability graphs of finite partially ordered sets (see \cite{Bres,Bres2,Bres3,Bres4} and \cite{Max,MaxDH}). We consider in s…

A rainbow version of Mantel's Theorem

1-subdivisions, fractional chromatic number and Hall ratio

Zeros of the Möbius function of permutations

On the growth of the Möbius function of permutations

Forbidden cycles in metrically homogeneous graphs

A 4-choosable graph that is not (8:2)-choosable

(3a:a)-list-colorability of embedded graphs of girth at least five

On difference graphs and the local dimension of posets

Single-conflict colouring

The Z2​-genus of Kuratowski minors

Structure and generation of crossing-critical graphs

Gray codes and symmetric chains

Planar graphs without cycles of length 4 or 5 are (11:3)-colorable

Algorithmic aspects of M-Lipschitz mappings of graphs

Characterizing subclasses of cover-incomparability graphs by forbidden subposets

A $4$ -choosable graph that is not $(8 : 2)$ -choosable

The $Z_{2}$ -genus of Kuratowski minors

Algorithmic aspects of $M$ -Lipschitz mappings of graphs