Results 21 to 30 of about 24,841 (222)

A proof of the stability of extremal graphs, Simonovits' stability from Szemer\'edi's regularity [PDF]

open access: yes, 2015
The following sharpening of Tur\'an's theorem is proved. Let $T_{n,p}$ denote the complete $p$--partite graph of order $n$ having the maximum number of edges. If $G$ is an $n$-vertex $K_{p+1}$-free graph with $e(T_{n,p})-t$ edges then there exists an (at
Füredi, Zoltán
core   +2 more sources

On a valence problem in extremal graph theory

open access: yesDiscrete Mathematics, 1973
Vorliegende Arbeit bezieht sich auf nicht-orientierte, Schlingen und mehrfache Kanten nicht enhaltende Graphen. Bezeichne \(L\) einen solchen vom vollständigen \(p\)-Graphen \(K_p\) verschiedenen \(p\)-chromatischen Graphen, welcher eine Kante \(e\) so enthält, daß \(L-e\) ein \((p-1)\)-chromatischer Graph ist. Als Hauptergebnis der vorliegenden Arbeit
Erdös, P., Simonovits, M.
openaire   +2 more sources

Characterizing extremal digraphs for identifying codes and extremal cases of Bondy's theorem on induced subsets [PDF]

open access: yes, 2012
An identifying code of a (di)graph $G$ is a dominating subset $C$ of the vertices of $G$ such that all distinct vertices of $G$ have distinct (in)neighbourhoods within $C$.
A. Winter   +15 more
core   +4 more sources

A Survey of Maximal k-Degenerate Graphs and k-Trees

open access: yesTheory and Applications of Graphs
This article surveys results on maximal $k$-degenerate graphs, $k$-trees, and related classes including simple $k$-trees, $k$-paths, maximal outerplanar graphs, and Apollonian networks.
Allan Bickle
doaj   +1 more source

Optimal transportation, topology and uniqueness [PDF]

open access: yes, 2010
The Monge-Kantorovich transportation problem involves optimizing with respect to a given a cost function. Uniqueness is a fundamental open question about which little is known when the cost function is smooth and the landscapes containing the goods to be
Ahmad, Najma   +2 more
core   +4 more sources

Problems in extremal graph theory [PDF]

open access: yes, 2010
We consider a variety of problems in extremal graph and set theory. The {\em chromatic number} of $G$, $\chi(G)$, is the smallest integer $k$ such that $G$ is $k$-colorable.
Ozkahya, Lale
core  

Turan problems in extremal graph theory and flexibility

open access: yes, 2021
In this work we will study two distinct areas of graph theory: generalized Turan problems and graph flexibility. In the first chapter, we will provide some basic definitions and motivation. Chapters 2 and 3 contain two submitted papers showing that two graphs, the cycle on five vertices and the path on four vertices, are maximized by the Turan graph ...
openaire   +4 more sources

Analysing the significance of small conformational changes and low occupancy states in serial crystallographic data

open access: yesFEBS Open Bio, EarlyView.
This protocol paper outlines methods to establish the success of a time‐resolved serial crystallographic experiment, by means of statistical analysis of timepoint data in reciprocal space and models in real space. We show how to amplify the signal from excited states to visualise structural changes in successful experiments.
Jake Hill   +4 more
wiley   +1 more source

Weighted Asymmetry Index: A New Graph-Theoretic Measure for Network Analysis and Optimization

open access: yesMathematics
Graph theory is a crucial branch of mathematics in fields like network analysis, molecular chemistry, and computer science, where it models complex relationships and structures.
Ali N. A. Koam   +3 more
doaj   +1 more source

On some extremal problems in graph theory

open access: yes, 1999
In this paper we are concerned with various graph invariants (girth, diameter, expansion constants, eigenvalues of the Laplacian, tree number) and their analogs for weighted graphs -- weighing the graph changes a combinatorial problem to one in analysis. We study both weighted and unweighted graphs which are extremal for these invariants.
Jakobson, Dmitry, Rivin, Igor
openaire   +2 more sources

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