Zobrazeno 1 - 10
of 131
pro vyhledávání: '"Jack H. Koolen"'
Publikováno v:
Journal of the Serbian Chemical Society, Vol 65, Iss 8, Pp 571-575 (2000)
If G is a molecular graph and l1, l2, ..., ln are its eigenvalues, then the energy of G is equal to E(G) = |l1| + |l2| + ... + |ln|. This energy cannot exceed the value . The graph G is said to be hyperenergetic if E(G) >> 2n - 2. We describe the con
Externí odkaz:
https://doaj.org/article/e42708f8420e45f898fa35f7d8ca91f2
Publikováno v:
Linear Algebra and its Applications. 670:1-18
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::efcddafccead1f96e1a111721373671b
https://doi.org/10.1016/j.laa.2023.03.029
https://doi.org/10.1016/j.laa.2023.03.029
Publikováno v:
Graphs and Combinatorics. 39
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::5689864009d91b9a8c1a9040ec8f9785
https://doi.org/10.1007/s00373-022-02606-8
https://doi.org/10.1007/s00373-022-02606-8
Publikováno v:
Graphs and Combinatorics. 38
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::77fbe4b833559360523d238a16ef3ba6
https://doi.org/10.1007/s00373-022-02573-0
https://doi.org/10.1007/s00373-022-02573-0
Publikováno v:
Graphs and Combinatorics. 37:1491-1507
In this paper, we discuss maximality of Seidel matrices with a fixed largest eigenvalue. We present a classification of maximal Seidel matrices of largest eigenvalue 3, which gives a classification of maximal equiangular lines in a Euclidean space wi
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::830e6ae2eaba77db985c1857dfd10840
https://doi.org/10.1007/s00373-021-02359-w
https://doi.org/10.1007/s00373-021-02359-w
Publikováno v:
Graphs and Combinatorics. 37:1139-1178
We give a survey on graphs with fixed smallest adjacency eigenvalue, especially on graphs with large minimal valency and also on graphs with good structures. Our survey mainly consists of the following two parts: At the end of the survey, we also dis
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::933f0545a4eee8836baf8b01c6179e6c
https://doi.org/10.1007/s00373-021-02296-8
https://doi.org/10.1007/s00373-021-02296-8
Publikováno v:
Discussiones Mathematicae Graph Theory, Vol 40, Iss 2, Pp 663-676 (2020)
A regular graph is co-edge regular if there exists a constant $\mu$ such that any two distinct and non-adjacent vertices have exactly $\mu$ common neighbors. In this paper, we show that for integers $s\ge 2$ and $n$ large enough, any co-edge-regular
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::5e1651af137ff5dc3289253a5729523a
https://doaj.org/article/8dae5ec58dc44c2ab9c80cdfb59ed529
https://doaj.org/article/8dae5ec58dc44c2ab9c80cdfb59ed529
Autor:
Qianqian Yang, Jack H. Koolen
Publikováno v:
Algebra Colloquium. 27:51-54
In this note we give several problems and conjectures on graphs with fixed smallest eigenvalue.
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::210bdb4266364f31d7f18698d5b5793e
https://doi.org/10.1142/s100538672000005x
https://doi.org/10.1142/s100538672000005x
Publikováno v:
Linear Algebra and its Applications. 587:271-290
In this paper, we consider the distance-regular graphs Γ whose distance-2 graphs Γ 2 are strongly regular. Note that if Γ is bipartite, then its distance-2 graph is not connected. We first show that the distance-2 graph of a non-bipartite distance
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::c8b445e9c2a1684d74db8dc2e5f58316
https://doi.org/10.1016/j.laa.2019.10.021
https://doi.org/10.1016/j.laa.2019.10.021
Publikováno v:
DESIGNS CODES AND CRYPTOGRAPHY
Designs, Codes and Cryptography, 90(9), 2003-2019. Springer
Designs, Codes and Cryptography, 90(9), 2003-2019. Springer
A Neumaier graph is a non-complete edge-regular graph containing a regular clique. In this paper we give some sufficient and necessary conditions for a Neumaier graph to be strongly regular. Further we show that there does not exist Neumaier graphs w
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::4ab17d84bd68783cdb5f3ee56bb6ccbe
https://biblio.ugent.be/publication/8712520/file/8716605
https://biblio.ugent.be/publication/8712520/file/8716605
