Ghorbani, Ebrahim; Haemers, Willem H.; Maimani, Hamid Reza; Majd, Leila Parsaei On sign-symmetric signed graphs. (English) Zbl 1465.05072 Ars Math. Contemp. 19, No. 1, 83-93 (2020). Summary: A signed graph is said to be sign-symmetric if it is switching isomorphic to its negation. Bipartite signed graphs are trivially sign-symmetric. We give new constructions of non-bipartite sign-symmetric signed graphs. Sign-symmetric signed graphs have a symmetric spectrum but not the other way around. We present constructions of signed graphs with symmetric spectra which are not sign-symmetric. This, in particular answers a problem posed by F. Belardo et al. [Art Discrete Appl. Math. 1, No. 2, Paper No. P2.10, 23 p. (2018; Zbl 1421.05052)]. Cited in 10 Documents MSC: 05C22 Signed and weighted graphs 05C50 Graphs and linear algebra (matrices, eigenvalues, etc.) Keywords:signed graph; spectrum Citations:Zbl 1421.05052 PDFBibTeX XMLCite \textit{E. Ghorbani} et al., Ars Math. Contemp. 19, No. 1, 83--93 (2020; Zbl 1465.05072) Full Text: DOI arXiv References: [1] S. Akbari, H. R. Maimani and L. Parsaei Majd, On the spectrum of some signed complete and complete bipartite graphs,Filomat32(2018), 5817-5826, doi:10.2298/fil1817817a. · Zbl 1499.05256 [2] F. Belardo, S. M. Cioab˘a, J. Koolen and J. Wang, Open problems in the spectral theory of signed graphs,Art Discrete Appl. Math.1(2018), #P2.10 (23 pages), doi:10.26493/2590-9770.1286. d7b. · Zbl 1421.05052 [3] F. Belardo and S. K. Simi´c, On the Laplacian coefficients of signed graphs,Linear Algebra Appl. 475(2015), 94-113, doi:10.1016/j.laa.2015.02.007. · Zbl 1312.05078 [4] A. E. Brouwer and W. H. Haemers,Spectra of Graphs, Universitext, Springer, New York, 2012, doi:10.1007/978-1-4614-1939-6. · Zbl 1231.05001 [5] F. C. Bussemaker, R. A. Mathon and J. J. Seidel, Tables of two-graphs, in: S. B. Rao (ed.), Combinatorics and Graph Theory, Springer, Berlin-New York, volume 885 ofLecture Notes in Mathematics, 1981 pp. 70-112, proceedings of the Second Symposium held at the Indian Statistical Institute, Calcutta, February 25 - 29, 1980. · Zbl 0482.05024 [6] G. Greaves, J. H. Koolen, A. Munemasa and F. Sz¨oll˝osi, Equiangular lines in Euclidean spaces, J. Comb. Theory Ser. A138(2016), 208-235, doi:10.1016/j.jcta.2015.09.008. · Zbl 1330.51006 [7] J. This reference list is based on information provided by the publisher or from digital mathematics libraries. Its items are heuristically matched to zbMATH identifiers and may contain data conversion errors. In some cases that data have been complemented/enhanced by data from zbMATH Open. This attempts to reflect the references listed in the original paper as accurately as possible without claiming completeness or a perfect matching.