Electronic Journal of Graph Theory and Applications (EJGTA)
Vol 13, No 1 (2025): Electronic Journal of Graph Theory and Applications

Hamiltonicity in directed Toeplitz graphs Tn⟨1, 3, 6; t⟩

Malik, Shabnam (Forman Christian College (A Chartered University) Lahore)



Article Info

Publish Date
28 Apr 2025

Abstract

A directed Toeplitz graph, denoted as Tn⟨s1, …, sk; t1, …, tl⟩ of order n, is a digraph in which an edge (i,  j) exists if and only if j − i = sp or i − j = tq for some 1 ≤ p ≤ k and 1 ≤ q ≤ l. The adjacency matrix of such a graph forms a Toeplitz matrix, characterized by constant values along all diagonals parallel to the main diagonal. In this paper, we explore the Hamiltonicity of directed Toeplitz graphs of the form Tn⟨1, 3, 6; t⟩. We establish that Tn⟨1, 3, 6; t⟩ is Hamiltonian for t = 5, 10 and for all t ≥ 12, for every n. Additionally, we show that the graph remains Hamiltonian for all n, with only a finite number of exceptions when t = 3, 4, 6, 7, 8, 9 and 11. Specifically, for t = 1, the graph is Hamiltonian only when n = 7, while for t = 2, it is Hamiltonian under certain conditions on n, namely when n ≡ 0, 1, 3 (mod 4). 

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Journal Info

Abbrev

ejgta

Publisher

Subject

Electrical & Electronics Engineering

Description

The Electronic Journal of Graph Theory and Applications (EJGTA) is a refereed journal devoted to all areas of modern graph theory together with applications to other fields of mathematics, computer science and other sciences. The journal is published by the Indonesian Combinatorial Society ...