Results 11 to 20 of about 1,080,603 (189)

Graphs of Morphisms of Graphs [PDF]

open access: yesThe Electronic Journal of Combinatorics, 2008
This is an account for the combinatorially minded reader of various categories of directed and undirected graphs, and their analogies with the category of sets. As an application, the endomorphisms of a graph are in this context not only composable, giving a monoid structure, but also have a notion of adjacency, so that the set of endomorphisms is both
Ronald Brown   +3 more
openaire   +3 more sources

Strong Oriented Chromatic Number of Planar Graphs without Short Cycles [PDF]

open access: yesDiscrete Mathematics & Theoretical Computer Science, 2008
Let M be an additive abelian group. An M-strong-oriented coloring of an oriented graph G is a mapping f from V(G) to M such that f(u) j(v) whenever uv is an arc in G and f(v)−f(u) −(f(t)−f(z)) whenever uv and zt are two arcs in G.
Mickael Montassier   +2 more
doaj   +1 more source

Embedding Graphs into Embedded Graphs [PDF]

open access: yesAlgorithmica, 2020
A (possibly denerate) drawing of a graph $G$ in the plane is approximable by an embedding if it can be turned into an embedding by an arbitrarily small perturbation. We show that testing, whether a straight-line drawing of a planar graph $G$ in the plane is approximable by an embedding, can be carried out in polynomial time, if a desired embedding of ...
openaire   +6 more sources

Relations between Spectrum Curves of Discrete Sturm-Liouville Problem with Nonlocal Boundary Conditions and Graph Theory. II

open access: yesLietuvos Matematikos Rinkinys, 2021
In this paper, relations between discrete Sturm--Liouville problem with nonlocal integral boundary condition characteristics (poles, critical points, spectrum curves) and graphs characteristics (vertices, edges and faces) were found. The previous article
Jonas Vitkauskas, Artūras Štikonas
doaj   +1 more source

Drawing by ear: interpreting sonified line graphs [PDF]

open access: yes, 2003
The research presented here describes a pilot study into the interpretation of sonified line graphs containing two data series. The experiment aimed to discover the level of accuracy with which sighted people were able to draw sketches of the graphs ...
Brewster, S.A., Brown, L.M.
core   +8 more sources

A Visualization Tool for Flood Dynamics Monitoring Using a Graph-Based Approach

open access: yesRemote Sensing, 2020
Insights into flood dynamics, rather than solely flood extent, are critical for effective flood disaster management, in particular in the context of emergency relief and damage assessment.
Bos Debusscher   +2 more
doaj   +1 more source

The Patterson function as auto-hologram and graph enables the direct solution to the phase problem for coherently illuminated atomistic structures

open access: yesNew Journal of Physics, 2021
The coherent Patterson function, derived from the coherent scattering intensities from N atoms, can be described as an auto-holographic image, i.e., the superposition of N -holographic images in which each atom serves as the source of a different ...
Irene Calvo-Almazán, Paul Fenter
doaj   +1 more source

An Analysis of the Use of Graphs in People’s Daily Life

open access: yesRevista Colombiana de Educación, 2021
This paper addresses the issue of the lack of connection between people’s knowledge and school mathematics. It is stated that this issue generates a phenomenon of opacity in People’s Daily Life and the uses of mathematical knowledge; this means that ...
José David Zaldívar-Rojas   +1 more
doaj   +1 more source

Graph Powers and Graph Homomorphisms [PDF]

open access: yesThe Electronic Journal of Combinatorics, 2010
In this paper, we investigate some basic properties of fractional powers. In this regard, we show that for any non-bipartite graph $G$ and positive rational numbers ${2r+1\over 2s+1} < {2p+1\over 2q+1}$, we have $G^{2r+1\over 2s+1} < G^{2p+1\over 2q+1}$. Next, we study the power thickness of $G$, that is, the supremum of rational numbers ${2r+
Hossein Hajiabolhassan, Ali Taherkhani
openaire   +3 more sources

Information Inequalities via Submodularity and a Problem in Extremal Graph Theory

open access: yesEntropy, 2022
The present paper offers, in its first part, a unified approach for the derivation of families of inequalities for set functions which satisfy sub/supermodularity properties.
Igal Sason
doaj   +1 more source

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