Determining finite connected graphs along the quadratic embedding constants of paths

The QE constant of a finite connected graph G, denoted by QEC(G), is by definition the maximum of the quadratic function associated to the distance matrix on a certain sphere of codimension two. We prove that the QE constants of paths Pn form a strictly increasing sequence converging to −1/2. Then w...

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Main Authors: Baskoro, Edy Tri; Combinatorial Mathematics Research Group Faculty of Mathematics and Natural Sciences Institut Teknologi Bandung Indonesia (Author), Obata, Nobuaki; Graduate School of Information Sciences Tohoku University Send (Author)
Other Authors: JSPS Open Partnership Joint Research Project (Contributor)
Format: EJournal Article
Published: GTA Research Group, Univ. Newcastle, Indonesian Combinatorics Society and ITB, 2021-10-16.
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042 |a dc 
100 1 0 |a Baskoro, Edy Tri; Combinatorial Mathematics Research Group Faculty of Mathematics and Natural Sciences Institut Teknologi Bandung Indonesia  |e author 
100 1 0 |a JSPS Open Partnership Joint Research Project  |e contributor 
700 1 0 |a Obata, Nobuaki; Graduate School of Information Sciences Tohoku University Send  |e author 
245 0 0 |a Determining finite connected graphs along the quadratic embedding constants of paths 
260 |b GTA Research Group, Univ. Newcastle, Indonesian Combinatorics Society and ITB,   |c 2021-10-16. 
500 |a https://www.ejgta.org/index.php/ejgta/article/view/1401 
520 |a The QE constant of a finite connected graph G, denoted by QEC(G), is by definition the maximum of the quadratic function associated to the distance matrix on a certain sphere of codimension two. We prove that the QE constants of paths Pn form a strictly increasing sequence converging to −1/2. Then we formulate the problem of determining all the graphs G satisfying QEC(Pn)≤QEC(G)<QEC(Pn + 1). The answer is given for n = 2 and n = 3 by exploiting forbidden subgraphs for QEC(G)< − 1/2 and the explicit QE constants of star products of the complete graphs. 
540 |a Copyright (c) 2021 Electronic Journal of Graph Theory and Applications (EJGTA) 
546 |a eng 
690 |a conditionally negative definite matrix; claw-free graphs; distance matrix; quadratic embedding constant; star product graph 
690 |a 05C50; 05C12; 05C76 
655 7 |a info:eu-repo/semantics/article  |2 local 
655 7 |a info:eu-repo/semantics/publishedVersion  |2 local 
655 7 |a Peer-reviewed Article  |2 local 
786 0 |n Electronic Journal of Graph Theory and Applications (EJGTA); Vol 9, No 2 (2021): Electronic Journal of Graph Theory and Applications; 539 - 560 
786 0 |n 2338-2287 
787 0 |n https://www.ejgta.org/index.php/ejgta/article/view/1401/pdf_198 
856 4 1 |u https://www.ejgta.org/index.php/ejgta/article/view/1401/pdf_198  |z Get Fulltext