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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

Showing 2009 · math.COShow all

20 papers · 2 filters

math.CO2009

Satisfying states of triangulations of a convex n-gon

Andrea Jiménez, Marcos Kiwi, Martin Loebl

In this work we count the number of satisfying states of triangulations of a convex n-gon using the transfer matrix method. We show an exponential (in n) lower bound. We also give…

math.CO2009★ 1 cited

Fractional total colourings of graphs of high girth

Tomas Kaiser, Andrew King, Daniel Kral

Reed conjectured that for every epsilon>0 and Delta there exists g such that the fractional total chromatic number of a graph with maximum degree Delta and girth at least g is at m…

math.CO2009★ 2 cited

Unexpected behaviour of crossing sequences

Matt DeVos, Bojan Mohar, Robert Samal

The n-th crossing number of a graph G, denoted cr_n(G), is the minimum number of crossings in a drawing of G on an orientable surface of genus n. We prove that for every a>b>0, the…

math.CO2009

An enumeration of equilateral triangle dissections

Ales Drapal, Carlo Hamalainen

We enumerate all dissections of an equilateral triangle into smaller equilateral triangles up to size 20, where each triangle has integer side lengths. A perfect dissection has no…

math.CO2009★ 15 cited

The extremal function for partial bipartite tilings

Codrut Grosu, Jan Hladky

For a fixed bipartite graph H and given number c, 0<c<1, we determine the threshold T_H(c) which guarantees that any n-vertex graph with at edge density at least T_H(c) contains $(…

math.CO2009★ 13 cited

Homomorphism and embedding universal structures for restricted classes

Jan Hubička, Jaroslav Nešetřil

This paper unifies problems and results related to (embedding) universal and homomorphism universal structures. On the one side we give a new combinatorial proof of the existence o…

math.CO2009

Non-representability of finite projective planes by convex sets

Martin Tancer

We prove that there is no d such that all finite projective planes can be represented by convex sets in R^d, answering a question of Alon, Kalai, Matousek, and Meshulam. Here, if P…

math.CO2009★ 22 cited

Short Cycle Covers of Cubic Graphs and Graphs with Minimum Degree Three

Tomas Kaiser, Daniel Kral, Bernard Lidicky +2

The Shortest Cycle Cover Conjecture of Alon and Tarsi asserts that the edges of every bridgeless graph with edges can be covered by cycles of total length at most …

math.CO2009★ 3 cited

Dualities and dual pairs in Heyting algebras

Jan Foniok, Jaroslav Nesetril, Ales Pultr +1

We extract the abstract core of finite homomorphism dualities using the techniques of Heyting algebras and (combinatorial) categories.

math.CO2009★ 1 cited

Latin bitrades, dissections of equilateral triangles and abelian groups

Ales Drapal, Carlo Hamalainen, Viteslav Kala

Let be a spherical latin bitrade. With each associate a set of linear equatio…

math.CO2009

Domination number of cubic graphs with large girth

Daniel Kral, Petr Skoda, Jan Volec

We show that every n-vertex cubic graph with girth at least g have domination number at most 0.299871n+O(n/g)<3n/10+O(n/g).

math.CO2009★ 5 cited

Filling the gap between Turán's theorem and Pósa's conjecture

Peter Allen, Julia Böttcher, Jan Hladký

Much of extremal graph theory has concentrated either on finding very small subgraphs of a large graph (Turan-type results) or on finding spanning subgraphs (Dirac-type results). I…

math.CO2009

An Eberhard-like theorem for pentagons and heptagons

Matt DeVos, Agelos Georgakopoulos, Bojan Mohar +1

Eberhard proved that for every sequence of non-negative integers satisfying Euler's formula , there are infinitely many…

math.CO2009★ 36 cited

Algebraic proof of Brooks' theorem

Jan Hladký, Daniel Král', Uwe Schauz

We give a proof of Brooks' theorem and its list coloring extension using the algebraic method of Alon and Tarsi; this also shows that the Brooks' theorem remains valid in a more ge…

math.CO2009★ 3 cited

Interleaved adjoints on directed graphs

Jan Foniok, Jaroslav Nesetril, Claude Tardif

For an integer k >= 1, the k-th interlacing adjoint of a digraph G is the digraph i_k(G) with vertex-set V(G)^k, and arcs ((u_1, ..., u_k), (v_1, ..., v_k)) such that (u_i,v_i) \in…

math.CO2009★ 1 cited

The tripartite Ramsey number for trees

Julia Böttcher, Jan Hladky, Diana Piguet

We prove that for all epsilon>0 there are c>0 and n_0 such that for all n>n_0 the following holds. For any two-colouring of the edges of one colour contains copies of a…

math.CO2009

Graphs with bounded tree-width and large odd-girth are almost bipartite

Alexandr V. Kostochka, Daniel Kral', Jean-Sebastien Sereni +1

We prove that for every and every , there exists such that every graph with tree-width at most and odd-girth at least has circular chromatic number a…

math.CO2009★ 89 cited

Characterisations and Examples of Graph Classes with Bounded Expansion

Jaroslav Nešetřil, Patrice Ossona de Mendez, David R. Wood

Classes with bounded expansion, which generalise classes that exclude a topological minor, have recently been introduced by Nešetřil and Ossona de Mendez. These classes are defined…

math.CO2009★ 8 cited

An improved linear bound on the number of perfect matchings in cubic graphs

Louis Esperet, Daniel Kral, Petr Skoda +1

We show that every cubic bridgeless graph with n vertices has at least 3n/4-10 perfect matchings. This is the first bound that differs by more than a constant from the maximal dime…

math.CO2009★ 8 cited

Circular edge-colorings of cubic graphs with girth six

D. Král', E. Mácajová, J. Mazák +1

We show that the circular chromatic index of a (sub)cubic graph with girth at least six is at most 7/2.