Research Article
Radio Labelings of Lexicographic Product of Some Graphs
Muhammad Shahbaz Aasi , Muhammad Asif , Tanveer Iqbal ,
and Muhammad Ibrahim
Centre for Advanced Studies in Pure and Applied Mathematics, Bahauddin Zakariya University, Multan, Pakistan
CorrespondenceshouldbeaddressedtoMuhammadShahbazAasi;mshahbazasi@gmail.com
Received 13 September 2021; Accepted 2 November 2021; Published 7 December 2021
AcademicEditor:AntonioDiCrescenzo
Copyright © 2021 Muhammad Shahbaz Aasi et al. is is an open access article distributed under the Creative Commons
AttributionLicense,whichpermitsunrestricteduse,distribution,andreproductioninanymedium,providedtheoriginalworkis
properly cited.
Labelingofgraphshasdefinedmanyvariationsintheliterature,e.g.,graceful,harmonious,andradiolabeling.Secrecyofdatain
datasciencesandininformationtechnologyisverynecessaryaswellastheaccuracyofdatatransmissionanddifferentchannel
assignments is maintained. It enhances the graph terminologies for the computer programs. In this paper, we will discuss
multidistanceradiolabelingusedforchannelassignmentproblemsoverwirelesscommunication.Aradiolabelingisaone-to-one
mapping ℘: V(G) ⟶ Z
+
satisfyingthecondition |℘(μ)− ℘(μ′ )| ≥ diam(G)+ 1 − d(μ, μ′ ): μ, μ′ ∈ V(G) foranypairofvertices
μ, μ′ in G.espanoflabeling ℘ isthelargestnumberthat ℘ assignstoavertexofagraph.Radionumberof G,denotedby rn(G),
istheminimumspantakenoverallradiolabelingsof G.Inthisarticle,wewillfindrelationsforradionumberandradiomean
number of a lexicographic product for certain families of graphs.
1. Introduction
enotionofgraphlabelingwasfirstintroducedin1966by
Rosa in [1], and since then, many different graph labelings
have been defined and studied. In the 19
th
century, for
studying the channel assignment problem, the term graph
labeling was used where the transmitters are used as the
verticesofthegraph.Twovertices(transmitters)aresaidto
be adjacent if they are sufficiently close to each other. A
model of the channel assignment problem was provided by
Hale[2]in1980.Basicnotionsanddefinitionscanbefound
in [3].
Let G �(V(G),E(G)) beaconnectedgraphwithvertex
set V(G) and edge set E(G). For any μ, μ
′
∈ V(G), let
d(μ, μ
′
) be the shortest length of the path between the
vertices μ and μ
′
. A distance-two labeling is a function
℘: V(G) ⟶ 1, 2, 3, ... ,k { } with span k having the maxi-
mum value k such that for any μ, μ
′
∈ V(G), μ ≠ μ
′
, the
following relations are satisfied:
|℘(μ)− ℘ μ
′
( | ≥
2, if d μ, μ
′
( � 1
1, if d μ, μ
′
( � 2
.
⎧⎨
⎩
(1)
In 1992, Griggs and Yeh [4] extensively studied about
distance-two labeling.
Anassignmentofpositiveintegerstotheverticesof G by
℘ of G is said to be a radio k-labeling if
|℘(μ)− ℘(μ
′
)| ≥ k + 1 − d(μ, μ
′
),where k isaninteger, k ≥ 1.
e span of labeling ℘, denoted by sp(℘), is the max
|℘(μ)− ℘(μ
′
)|: μ, μ
′
∈ V(G) .Radionumberof G,denoted
by rn(G),istheminimumspantakenoverallradiolabelings
of G.eradio k-labelingnumberof G istheminimumspan
among all radio k-labelings of G.
e study of radio k-labelings was motivated by Char-
trandetal.[5]wheretheyfoundtheradio k-labelingnumber
forpaths.In[5],thelowerandupperboundsweregivenfor
the radio k-labeling number for paths which have been
improved lately by Kchikech et al. [6]. e radio k-labeling
becomes a radio labeling, when k � diam(G). A radio la-
beling is a mapping from the vertices of the graph to some
subsets of positive integers. e task of radio labeling is to
assigntoeachstationapositivesmallestintegersuchthatthe
interferenceinthenearestchannelshouldbeminimized.In
2001, multilevel distance labeling problem was introduced
by Chartrand et al. [7].
Hindawi
Journal of Mathematics
Volume 2021, Article ID 9177818, 6 pages
https://doi.org/10.1155/2021/9177818