Modular Version of Edge Irregularity Strength for Fan and Wheel Graphs

oleh: Debi Oktia Haryeni, Zata Yumni Awanis, Martin Bača, Andrea Semaničová-Feňovčíková

Format: Article
Diterbitkan: MDPI AG 2022-12-01

Deskripsi

A <i>k</i>-labeling from the vertex set of a simple graph <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>G</mi><mo>=</mo><mo>(</mo><mi>V</mi><mo>,</mo><mi>E</mi><mo>)</mo></mrow></semantics></math></inline-formula> to a set of integers <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>{</mo><mn>1</mn><mo>,</mo><mn>2</mn><mo>,</mo><mo>…</mo><mo>,</mo><mi>k</mi><mo>}</mo></mrow></semantics></math></inline-formula> is defined to be a modular edge irregular if, for every couple of distinct edges, their modular edge weights are distinct. The modular edge weight is the remainder of the division of the sum of end vertex labels by modulo <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>|</mo><mi>E</mi><mo>(</mo><mi>G</mi><mo>)</mo><mo>|</mo></mrow></semantics></math></inline-formula>. The modular edge irregularity strength of a graph is known as the maximal vertex label <i>k</i>, minimized over all modular edge irregular <i>k</i>-labelings of the graph. In this paper we describe labeling schemes with symmetrical distribution of even and odd edge weights and investigate the existence of (modular) edge irregular labelings of joins of paths and cycles with isolated vertices. We estimate the bounds of the (modular) edge irregularity strength for the join graphs <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>P</mi><mi>n</mi></msub><mo>+</mo><mover><msub><mi>K</mi><mi>m</mi></msub><mo>¯</mo></mover></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>C</mi><mi>n</mi></msub><mo>+</mo><mover><msub><mi>K</mi><mi>m</mi></msub><mo>¯</mo></mover></mrow></semantics></math></inline-formula> and determine the corresponding exact value of the (modular) edge irregularity strength for some fan graphs and wheel graphs in order to prove the sharpness of the presented bounds.