H. Topcu

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20152023

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4 papers · 1 filter

math.CO2023

Cospectrality results for signed graphs with two eigenvalues unequal to $\pm 1$

Willem H. Haemers, Hatice Topcu

Recently the collection $G$ of all signed graphs for which the adjacency matrix has all but at most two eigenvalues equal to $\pm 1$ has been determined. Here we investigate $…

math.CO2021

On signed graphs with at most two eigenvalues unequal to $\pm 1$

Willem H. Haemers, Hatice Topcu

We present the first steps towards the determination of the signed graphs for which the adjacency matrix has all but at most two eigenvalues equal to 1 or -1. Here we deal with the…

math.CO2018

On the spectral characterization of mixed extensions of $P_{3}$

Willem H. Haemers, Sezer Sorgun, Hatice Topcu

A mixed extension of a graph $G$ is a graph $H$ obtained from $G$ by replacing each vertex of $G$ by a clique or a coclique, whilst two vertices in $H$ corresponding to distinct ve…

math.CO2015

On the spectral characterization of Kite graphs

Sezer Sorgun, Hatice Topcu

The \textit{Kite graph}, denoted by $K i t e_{p, q}$ is obtained by appending a complete graph $K_{p}$ to a pendant vertex of a path $P_{q}$ . In this paper, firstly we show that no two…

Cospectrality results for signed graphs with two eigenvalues unequal to ±1

On signed graphs with at most two eigenvalues unequal to ±1

On the spectral characterization of mixed extensions of P3​

On the spectral characterization of Kite graphs

Cospectrality results for signed graphs with two eigenvalues unequal to $\pm 1$

On signed graphs with at most two eigenvalues unequal to $\pm 1$

On the spectral characterization of mixed extensions of $P_{3}$