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A nut graph is a simple graph whose adjacency matrix has the eigenvalue zero with multiplicity one such that its corresponding eigenvector has no zero entries. It is known that there exist no cubic circulant nut graphs. A bicirculant (resp.…

Combinatorics · Mathematics 2024-05-27 Ivan Damnjanović , Nino Bašić , Tomaž Pisanski , Arjana Žitnik

A nut graph is a simple graph of order 2 or more for which the adjacency matrix has a single zero eigenvalue such that all non-zero kernel eigenvectors have no zero entry (i.e. are full). It is shown by construction that every finite group…

Combinatorics · Mathematics 2024-05-08 Nino Bašić , Patrick W. Fowler

A circulant graph is a simple graph whose adjacency matrix can be represented in the form of a circulant matrix, while a nut graph is considered to be a graph whose null space is spanned by a single full vector. In a previous study by…

Combinatorics · Mathematics 2026-01-26 Ivan Damnjanović

A nut graph is a simple graph for which the adjacency matrix has a single zero eigenvalue such that all non-zero kernel eigenvectors have no zero entry. If the isolated vertex is excluded as trivial, nut graphs have seven or more vertices;…

Combinatorics · Mathematics 2023-12-07 Nino Bašić , Patrick W. Fowler , Tomaž Pisanski

A nut graph is a nontrivial simple graph whose adjacency matrix contains a one-dimensional null space spanned by a vector without zero entries. Moreover, an $\ell$-circulant graph is a graph that admits a cyclic group of automorphisms…

Combinatorics · Mathematics 2025-06-09 Nino Bašić , Ivan Damnjanović

A nut graph is a simple graph whose adjacency matrix has the eigenvalue~0 with multiplicity~1 such that its corresponding eigenvector has no zero entries. Motivated by a question of Fowler et al.~[\emph{Disc. Math. Graph Theory} 40 (2020),…

Combinatorics · Mathematics 2021-06-03 Ivan Damnjanović , Dragan Stevanović

A nut graph is a simple graph whose kernel is spanned by a single full vector (i.e. the adjacency matrix has a single zero eigenvalue and all non-zero kernel eigenvectors have no zero entry). We classify generalisations of nut graphs to nut…

Combinatorics · Mathematics 2025-03-14 Nino Bašić , Patrick W. Fowler , Maxine M. McCarthy , Primož Potočnik

Nut graphs are graphs whose adjacency matrix is singular with one-dimensional null space spanned by a vector with no zero entries. In a recent paper, Ba\v{s}i\'c, Fowler and Pisanski proved that the automorphism group of a nut graph has…

Combinatorics · Mathematics 2025-08-26 Ksenija Rozman , Primož Šparl

A nut graph is a simple graph whose adjacency matrix is singular with $1$-dimensional kernel such that the corresponding eigenvector has no zero entries. In 2020, Fowler et al. characterised for each $d \in \{3,4,\ldots,11\}$ all values $n$…

Combinatorics · Mathematics 2021-02-09 Nino Bašić , Martin Knor , Riste Škrekovski

A finite graph is called a tricirculant if admits a cyclic group of automorphism which has precisely three orbits on the vertex-set of the graph, all of equal size. We classify all finite connected cubic vertex-transitive tricirculants. We…

Combinatorics · Mathematics 2018-12-12 Primož Potočnik , Micael Toledo

A nut graph is a nontrivial graph whose adjacency matrix has a one-dimensional null space spanned by a vector without zero entries. Recently, it was shown that a nut graph has more edge orbits than vertex orbits. It was also shown that for…

Combinatorics · Mathematics 2026-01-26 Nino Bašić , Ivan Damnjanović

A graph $G$ with four or more vertices is called bicritical if the removal of any pair of distinct vertices of $G$ results in a graph with a perfect matching. A bicritical graph is minimal if the deletion of each edge results in a…

Combinatorics · Mathematics 2024-10-15 Jing Guo , Hailun Wu , Heping Zhang

A nut graph is a graph on at least 2 vertices whose adjacency matrix has nullity 1 and for which non-trivial kernel vectors do not contain a zero. Chemical graphs are connected, with maximum degree at most three. We present a new algorithm…

Combinatorics · Mathematics 2017-09-14 Kris Coolsaet , Patrick W. Fowler , Jan Goedgebeur

An eigenvalue of a graph $G$ is called a main eigenvalue if it has an eigenvector the sum of whose entries is not equal to zero. In this paper, all connected tricyclic graphs with exactly two main eigenvalues are determined.

Mathematical Physics · Physics 2014-10-31 He Huang , Hanyuan Deng

An eigenvalue of a graph $G$ is called a main eigenvalue if it has an eigenvector the sum of whose entries is not equal to zero. In this paper, all connected tricyclic graphs with exactly two main eigenvalues are determined.

Combinatorics · Mathematics 2010-12-07 Xiaoxia Fan , Yanfeng Luo

A connected graph of order $n$ admitting a semiregular automorphism of order $n/k$ is called a $k$-multicirculant. Highly symmetric multicirculants of small valency have been extensively studied, and several classification results exist for…

Combinatorics · Mathematics 2022-08-15 Primož Potočnik , Micael Toledo

A nut graph is a singular graph with one-dimensional kernel and corresponding eigenverctor with no zero elements. The problem of determining the orders $n$ for which $d$-regular nut graphs exist was recently posed by Gauci, Pisanski and…

Combinatorics · Mathematics 2019-11-07 Patrick W. Fowler , John Baptist Gauci , Jan Goedgebeur , Tomaž Pisanski , Irene Sciriha

A circulant nut graph is a non-trivial simple graph whose adjacency matrix is a circulant matrix of nullity one such that its non-zero null space vectors have no zero elements. The study of circulant nut graphs was originally initiated by…

Combinatorics · Mathematics 2024-05-27 Ivan Damnjanović

A nut graph is a simple graph for which the adjacency matrix has a single zero eigenvalue such that all non-zero kernel eigenvectors have no zero entry. It is known that infinitely many $d$-regular nut graphs exist for $3 \leq d \leq 12$…

Combinatorics · Mathematics 2025-06-05 Nino Bašić , Ivan Damnjanović , Patrick W. Fowler

A bicirculant is a regular graph that admits an automorphism having two vertex-orbits of the same size. A bicirculant can be described as follows. Given an integer $m \ge 1$ and sets $R, S, T \subseteq \mathbb Z_m$ such that $R=-R$, $T=-T$,…

Combinatorics · Mathematics 2026-04-24 Simona Bonvicini , Tomaž Pisanski , Arjana Žitnik
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