Search results for " graph"

Three-dimensional interpretation of the color system of Aguilonius/Rubens 1613

2000

The two-dimensional color system in the textbook on optics, written by F. Aguilonius (1613) and illustrated by PP Rubens,1 is equivalent to a three-dimensional color solid, which can also be constructed by applying the trichromatic theory of color vision on a color circle. © 2000 John Wiley & Sons, Inc. Col Res Appl, 26, S17–S19, 2001

Software for simulating dichromatic perception of video streams

2013

We have designed a configurable stand-alone Matlab-based software to simulate dichromatic perception of video streams. The algorithm used is an extension for video streams of the “corresponding pair algorithm” by Capilla and coworkers for simulation of dichromatic perception of images. The software allows the user to upload a video sequence and to process it using different dichromatic color vision models and viewing conditions. The output video may be generated in different spatial and temporal resolutions and file formats. The functions for Matlab environment and a stand-alone application may be downloaded from the Repository of the University of Alicante. © 2013 Wiley Periodicals, Inc. C…

Prototype selection for the nearest neighbour rule through proximity graphs

1997

Abstract In this paper, the Gabriel and Relative Neighbourhood graphs are used to select a suitable subset of prototypes for the Nearest Neighbour rule. Experiments and results are reported showing the effectiveness of the method and comparing its performance to those obtained by classical techniques.

Two groups with isomorphic group algebras

1990

The irregularity strength of circulant graphs

2005

AbstractThe irregularity strength of a simple graph is the smallest integer k for which there exists a weighting of the edges with positive integers at most k such that all the weighted degrees of the vertices are distinct. In this paper we study the irregularity strength of circulant graphs of degree 4. We find the exact value of the strength for a large family of circulant graphs.

Remarks on Partially Square Graphs, Hamiltonicity and Circumference

2001

Multilevel Bandwidth and Radio Labelings of Graphs

2008

This paper introduces a generalization of the graph bandwidth parameter: for a graph G and an integer k ≤ diam(G), the k-level bandwidth Bk(G)of G is defined by Bk(G) = minγ max{|γ(x)-γ(y)|-d(x, y)+1 : x, y ∈ V (G), d(x, y) ≤ k}, the minimum being taken among all proper numberings γ of the vertices of G. We present general bounds on Bk(G) along with more specific results for k = 2 and the exact value for k = diam(G). We also exhibit relations between the k-level bandwidth and radio k-labelings of graphs from which we derive a upper bound for the radio number of an arbitrary graph.

When can an equational simple graph be generated by hyperedge replacement?

1998

Infinite hypergraphs with sources arise as the canonical solutions of certain systems of recursive equations written with operations on hypergraphs. There are basically two different sets of such operations known from the literature, HR and VR. VR is strictly more powerful than HR on simple hypergraphs. Necessary conditions are known ensuring that a VR-equational simple hypergraph is also HR-equational. We prove that two of them, namely having finite tree-width or not containing the infinite bipartite graph, are also sufficient. This shows that equational hypergraphs behave like context-free sets of finite hypergraphs.

Centralizers of Parabolic Subgroups of Artin Groups of TypeAl,Bl, andDl

1997

Abstract Let ( A , Σ) be an Artin system of one of the types A l , B l , D l . For X  ⊆ Σ, we denote by A X the subgroup of A generated by X . Such a group is called a parabolic subgroup of ( A , Σ). Let A X be a parabolic subgroup with connected associated Coxeter graph. We exhibit a generating set of the centralizer of A X in A . Moreover, we prove that there exists X ′ ⊆ Σ such that A X ′ is conjugate to A X and such that the centralizer of A X ′ in A is generated by the centers of all the parabolic subgroups containing A X ′ .

Incomplete vertices in the prime graph on conjugacy class sizes of finite groups

2013

Abstract Given a finite group G, consider the prime graph built on the set of conjugacy class sizes of G. Denoting by π 0 the set of vertices of this graph that are not adjacent to at least one other vertex, we show that the Hall π 0 -subgroups of G (which do exist) are metabelian.