S. A. Mojallal

activity

20172026

most citedRiordan graphs II: Spectral properties

1 citations · 2 across the 15 of their papers we have counts for

collaborators

16 papers

math.CO2026

A proof of the maximum Laplacian energy conjecture for connected graphs via a sharp eigenvalue-sum bound

Seyed Ahmad Mojallal

Let $S_{k} (G)$ denote the sum of the $k$ largest Laplacian eigenvalues of a connected graph $G$ of order $n$ and size $m$ . Write $PA_{n, ω}$ for the graph obtained from an $ω…

math.FA2026

Stability of maximal relative projection constants

Hitesh Kumar, Bojan Mohar, Seyed Ahmad Mojallal +1

For positive integers $n \geq r$ , let $λ (r, n)$ denote the \emph{maximal relative projection constant} of $r$ -dimensional subspaces of $ℓ_{\infty}^{n}$ and $λ (r)$ denote the \emph{maxi…

math.CO2026

Rank-Average Degree Bound for Graph Energy

Seyed Ahmad Mojallal

We prove that the energy $E (G)$ of any simple graph $G$ of order $n \geq 5$ satisfies \[ {\mathcal E}\ge r(G)+\bar d(G)-1, \] where $r (G)$ and $d ˉ (G)$ denote, respectiv…

math.CO2026

Extremal Graphs for the Energy-Independence Number Inequality

Seyed Ahmad Mojallal

For a graph $G$ of order $n$ , let $E (G)$ denote its adjacency energy and let $α (G)$ denote its independence number. A recent theorem of Kumar and Pragada states that $$\ma…

math.CO2026

Extremal graphs for the $k$ -th eigenvalue

Hitesh Kumar, Bojan Mohar, Seyed Ahmad Mojallal +1

For a simple graph $G$ of order $n$ , let $λ_{1} (G) \geq \dots \geq λ_{n} (G)$ denote its adjacency eigenvalues. Hong's problem asks for the optimal upper bound for $λ_{k} (G)$ . A recent theo…

cs.LG2025

Distance-based Learning of Hypertrees

Shaun Fallat, Kamyar Khodamoradi, David Kirkpatrick +3

We study the problem of learning hypergraphs with shortest-path queries (SP-queries), and present the first provably optimal online algorithm for a broad and natural class of hyper…

math.CO2023

Forts, (fractional) zero forcing, and Cartesian products of graphs

Thomas R. Cameron, Leslie Hogben, Franklin H. J. Kenter +2

The (disjoint) fort number and fractional zero forcing number are introduced and related to existing parameters including the (standard) zero forcing number. The fort hypergraph is…

math.CO2023

Spectral Applications of Vertex-Clique Incidence Matrices Associated with a Graph

Shaun Fallat, Seyed Ahmad Mojallal

In this paper, we demonstrate a useful interaction between the theory of clique partitions, edge clique covers of a graph, and the spectra of graphs. Using a clique partition and a…

math.CO2023

The $q$ -Analogue of Zero Forcing for Certain Families of Graphs

Shaun Fallat, Neha Joshi, Roghayeh Maleki +6

Zero forcing is a combinatorial game played on a graph with the ultimate goal of changing the colour of all the vertices at minimal cost. Originally this game was conceived as a on…

math.CO2022

On Toeplitz graphs being line graphs

Gi-Sang Cheon, Bumtle Kang, Suh-Ryung Kim +2

A Toeplitz graph $T_{n} ⟨ t_{1}, t_{2}, \dots, t_{k} ⟩$ is a simple graph with the vertex set $[n]$ such that two vertices $v$ and $w$ are adjacent if and only if $∣ v - w ∣ = t_{i}$ fo…

math.CO2021

Structural properties of Toeplitz graphs

Seyed Ahmad Mojallal, Ji-Hwan Jung, Gi-Sang Cheon +2

In this paper, we study structural properties of Toeplitz graphs. We characterize $K_{q}$ -free Toeplitz graphs for an integer $q \geq 3$ and give equivalent conditions for a Toeplitz…

math.CO2021

On the minimum number of distinct eigenvalues of a threshold graph

Shaun Fallat, Seyed Ahmad Mojallal

For a graph $G$ , we associate a family of real symmetric matrices, $S (G)$ , where for any $A \in S (G)$ , the location of the nonzero off-diagonal entries of $A$ are governed by the ad…

math.CO2020

Counting independent sets in Riordan graphs

Gi-Sang Cheon, Ji-Hwan Jung, Bumtle Kang +4

The notion of a Riordan graph was introduced recently, and it is a far-reaching generalization of the well-known Pascal graphs and Toeplitz graphs. However, apart from a certain su…

math.CO2018★ 1 cited

Riordan graphs II: Spectral properties

Gi-Sang Cheon, Ji-Hwan Jung, Sergey Kitaev +1

The authors of this paper have used the theory of Riordan matrices to introduce the notion of a Riordan graph in \cite{CJKM}. Riordan graphs are proved to have a number of interest…

math.CO2017

Open problem on $σ$ -invariant

Kinkar Ch. Das, Seyed Ahmad Mojallal

Let $G$ be a graph of order $n$ with $m$ edges. Also let $μ_{1} \geq μ_{2} \geq \dots \geq μ_{n - 1} \geq μ_{n} = 0$ be the Laplacian eigenvalues of graph $G$ and let $σ = σ (G)$ $(1 \leq σ \leq n)$ …

math.CO2017★ 1 cited

Riordan graphs I: Structural properties

Gi-Sang Cheon, Ji-Hwan Jung, Sergey Kitaev +1

In this paper, we use the theory of Riordan matrices to introduce the notion of a Riordan graph. The Riordan graphs are a far-reaching generalization of the well known and well stu…

A proof of the maximum Laplacian energy conjecture for connected graphs via a sharp eigenvalue-sum bound

Stability of maximal relative projection constants

Rank-Average Degree Bound for Graph Energy

Extremal Graphs for the Energy-Independence Number Inequality

Extremal graphs for the k-th eigenvalue

Distance-based Learning of Hypertrees

Forts, (fractional) zero forcing, and Cartesian products of graphs

Spectral Applications of Vertex-Clique Incidence Matrices Associated with a Graph

The q-Analogue of Zero Forcing for Certain Families of Graphs

On Toeplitz graphs being line graphs

Structural properties of Toeplitz graphs

On the minimum number of distinct eigenvalues of a threshold graph

Counting independent sets in Riordan graphs

Riordan graphs II: Spectral properties

Open problem on σ-invariant

Riordan graphs I: Structural properties

Extremal graphs for the $k$ -th eigenvalue

The $q$ -Analogue of Zero Forcing for Certain Families of Graphs

Open problem on $σ$ -invariant