Electronic Journal of Graph Theory and Applications (EJGTA)
Vol 14, No 1 (2026): Electronic Journal of Graph Theory and Applications

Modular irregularity strength of vertex amalgamation and comb product path with cycle related graphs

Sugeng, Kiki A. (Universitas Indonesia)
Sofyan, Fawwaz Chirag (Combinatorics and Algebra Research Group, Department of Mathematics, Faculty of Mathematics and Natural Sciences, Universitas Indonesia, Indonesia)
Sy, Syafrizal (Department of Mathematics and Data Science, Faculty of Mathematics and Natural Sciences, Andalas University, Padang, Indonesia)
Hinding, Nurdin (Graph Theory Research Group, Department of Mathematics, Faculty of Mathematics and Natural Sciences, Hasanuddin University, Indonesia)
Simanjuntak, Rinovia (Combinatorial Mathematics Research Group, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Indonesia)



Article Info

Publish Date
22 Apr 2026

Abstract

Consider a graph G = (V(G), E(G)), where V(G) is a nonempty set of vertices and E(G) is a set of edges. Let Zn be the group of integers modulo n, and let k be a positive integer. A modular irregular labeling of a graph G of order n is a k-edge labeling ϕ : E(G) → {1, 2, … , k}, such that an induced weight function wtϕ : V(G) → Zn is bijective. The weight function is defined as follows: wtϕ(u) = Σu ∈ N(v) ϕ(uv) (mod n) for all vertices v in V(G). The minimum value of k is called the modular irregularity strength of G, denoted as ms(G). Suppose G and H are two connected graphs, with G has order n. Vertex amalgamation of graphs G and H is a graph obtained by identifying one vertex from each graph. Suppose that o is a given vertex of H. The comb product of G ▷ H is the graph obtained by taking one copy of G and n copies of H and then attaching the vertex o of the i-th copy of H to the i-th vertex of G. In this paper, we discuss on the exact values of the modular irregularity strength for several graphs such as: vertex amalgamation of cycles; comb product path (or cycle) and cycle and comb product path (or cycle) and regular graphs.

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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 ...