4 citations · 7 across the 5 of their papers we have counts for
8 papers
On singular signed graphs with nullspace spanned by a full vector: Signed nut graphs
Nino Bašić, Patrick W. Fowler, Tomaž Pisanski +1
A signed graph has edge weights drawn from the set , and is termed sign-balanced if it is equivalent to an unsigned graph under the operation of sign switching; otherwis…
Nullspace Vertex Partition in Graphs
Irene Sciriha, Xandru Mifsud, James Borg
The core vertex set of a graph is an invariant of the graph. It consists of those vertices associated with the non-zero entries of the nullspace vectors of a -adjacency ma…
Existence of regular nut graphs for degree at most 11
Patrick W. Fowler, John Baptist Gauci, Jan Goedgebeur +2
A nut graph is a singular graph with one-dimensional kernel and corresponding eigenverctor with no zero elements. The problem of determining the orders for which -regular nu…
On the Walks and Bipartite Double Coverings of Graphs with the same Main Eigenspace
Luke Collins, Irene Sciriha
The main eigenvalues of a graph are those eigenvalues of the -adjacency matrix having a corresponding eigenvector not orthogonal to …
On the Displacement of Eigenvalues when Removing a Twin Vertex
Johann A. Briffa, Irene Sciriha
Twin vertices of a graph have the same open neighbourhood. If they are not adjacent, then they are called duplicates and contribute the eigenvalue zero to the adjacency matrix. Oth…
Existence of Regular Nut Graphs and the Fowler Construction
John Baptist Gauci, Tomaz Pisanski, Irene Sciriha
In this paper the problem of the existence of regular nut graphs is addressed. A generalization of Fowler's Construction which is a local enlargement applied to a vertex in a graph…
Fast Algorithms for Indices of Nested Split Graphs Approximating Real Complex Networks
Irene Sciriha, Johann A. Briffa, Mark Debono
We present a method based on simulated annealing to obtain a nested split graph that approximates a real complex graph. This is used to compute a number of graph indices using very…
Graphs that have a weighted adjacency matrix with spectrum
Karen Meagher, Irene Sciriha
In this paper we completely characterize the graphs which have an edge weighted adjacency matrix belonging to the class of involutions with spectrum equal to $\{ λ_1^{…