On the existence of semigraphs and complete semigraphs with given parameters

E. Sampathkumar has generalized a graph to a semigraph by allowing an edge to have more than two vertices. Like in the case of graphs, a complete semigraph is a semigraph in which every two vertices are adjacent to each other. In this article, we have generalized a problem noted by Gauss in 1796 abo...

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Autores principales: Jyoti Shetty, G. Sudhakara, Vinay Madhusudanan
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Lenguaje:EN
Publicado: Elsevier 2021
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spelling oai:doaj.org-article:6539e4e600cc43f7bdc829b8900840892021-11-22T04:21:26ZOn the existence of semigraphs and complete semigraphs with given parameters2090-447910.1016/j.asej.2021.04.002https://doaj.org/article/6539e4e600cc43f7bdc829b8900840892021-12-01T00:00:00Zhttp://www.sciencedirect.com/science/article/pii/S2090447921001611https://doaj.org/toc/2090-4479E. Sampathkumar has generalized a graph to a semigraph by allowing an edge to have more than two vertices. Like in the case of graphs, a complete semigraph is a semigraph in which every two vertices are adjacent to each other. In this article, we have generalized a problem noted by Gauss in 1796 about triangular numbers and shown that it is the deciding factor of when a semigraph is complete.Let P be a set with p elements and {E1,E2,…,Eq} be a collection of subsets of P with ⋃i=1qEi=P. We derive an expression for the maximum value of the difference ∑j=1k|Eij|-⋃i=1kEij for 2⩽k⩽q, where every two of the sets in the collection can have at most one element in common. We show that this result helps in answering the question of whether there exists a semigraph on the vertex set P having edges {e1,e2,…,eq}, where the set Ei is the set of vertices on the edge ei,1⩽i⩽q. Combining the above two results, we characterize a complete semigraph.Jyoti ShettyG. SudhakaraVinay MadhusudananElsevierarticleComplete semigraphTriangular numbersVertex degreeEngineering (General). Civil engineering (General)TA1-2040ENAin Shams Engineering Journal, Vol 12, Iss 4, Pp 4119-4124 (2021)
institution DOAJ
collection DOAJ
language EN
topic Complete semigraph
Triangular numbers
Vertex degree
Engineering (General). Civil engineering (General)
TA1-2040
spellingShingle Complete semigraph
Triangular numbers
Vertex degree
Engineering (General). Civil engineering (General)
TA1-2040
Jyoti Shetty
G. Sudhakara
Vinay Madhusudanan
On the existence of semigraphs and complete semigraphs with given parameters
description E. Sampathkumar has generalized a graph to a semigraph by allowing an edge to have more than two vertices. Like in the case of graphs, a complete semigraph is a semigraph in which every two vertices are adjacent to each other. In this article, we have generalized a problem noted by Gauss in 1796 about triangular numbers and shown that it is the deciding factor of when a semigraph is complete.Let P be a set with p elements and {E1,E2,…,Eq} be a collection of subsets of P with ⋃i=1qEi=P. We derive an expression for the maximum value of the difference ∑j=1k|Eij|-⋃i=1kEij for 2⩽k⩽q, where every two of the sets in the collection can have at most one element in common. We show that this result helps in answering the question of whether there exists a semigraph on the vertex set P having edges {e1,e2,…,eq}, where the set Ei is the set of vertices on the edge ei,1⩽i⩽q. Combining the above two results, we characterize a complete semigraph.
format article
author Jyoti Shetty
G. Sudhakara
Vinay Madhusudanan
author_facet Jyoti Shetty
G. Sudhakara
Vinay Madhusudanan
author_sort Jyoti Shetty
title On the existence of semigraphs and complete semigraphs with given parameters
title_short On the existence of semigraphs and complete semigraphs with given parameters
title_full On the existence of semigraphs and complete semigraphs with given parameters
title_fullStr On the existence of semigraphs and complete semigraphs with given parameters
title_full_unstemmed On the existence of semigraphs and complete semigraphs with given parameters
title_sort on the existence of semigraphs and complete semigraphs with given parameters
publisher Elsevier
publishDate 2021
url https://doaj.org/article/6539e4e600cc43f7bdc829b890084089
work_keys_str_mv AT jyotishetty ontheexistenceofsemigraphsandcompletesemigraphswithgivenparameters
AT gsudhakara ontheexistenceofsemigraphsandcompletesemigraphswithgivenparameters
AT vinaymadhusudanan ontheexistenceofsemigraphsandcompletesemigraphswithgivenparameters
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