This research delves into the pathway energy framework for flower families, a class of simple connected graphs, whose path matrix is constructed such that each entry quantifies the maximum number of vertex-disjoint paths. By analyzing the characteristic values of this matrix, we establish the pathway energy bounds specific to these flower graph families. Additionally, a comprehensive algorithm is developed to evaluate the time complexity across different flower family configurations, utilizing numerous trials to capture their average, maximum, and minimum computational behaviors. This analysis offers a comparative study of the structural intricacies that lead to increased computational complexity, highlighting which graph topologies tend to impose higher algorithmic challenges. The proposed method introduces a refined and adaptable approach, deepening the exploration of characteristic graph properties and their computational impact, thereby expanding the practical applications of these findings in graph theory.
Keywords: Characteristics values, Flower families, Energy, Pathway Energy, Time complexity
1. Introduction
Consider an undirected graph , where represents the set of vertices and
denotes the set of edges [5]. The concept of graph energy,
first introduced by Ivan Gutman [10,23] in 1978, emerged as a refined extension of
the Hückel Molecular Orbital (HMO) theory, originally formulated to
quantify the total -electron
energy in molecular systems.
Following this, the concept of graph energy resurfaced as a
significant and highly researched theme within chemical graph theory
[23], leading to a surge in
academic attention, with more than a hundred research papers published
annually [11,12]. Numerous
properties and well-established bounds associated with graph energy have
since been developed and explored extensively [2,3,6].A molecular graph with vertices. The eigenvalues of the -adjacency matrix of , denoted by ,
constitute the spectrum of . The
total sum of the absolute values of the eigenvalues of defines the energy of the graph
[10,24].
In this framework, Patekar et al. introduced a novel concept called
the pathway matrix [17,20],
which leads to the definition of path energy for a graph, extending the
classical notion of graph energy. Define a matrix of dimension , where for , represents the greatest number of
vertex-disjoint paths from vertex to vertex . For the case where , set . In the paper by Sabeen et al.
[19], the author explores
the pathway energy across
various graph classes, deriving key conclusions about the behavior of
path energy. Similarly,
Raza et al. [18] in 2023 dig
into the spectrum of graphs. In a related study, Xu and Zhou [22] identify the graphs that attain
both upper and lower bounds on the path index for graphs with specified
structural parameters. In the book by Cvetkovski et al. [7], the authors examine a variety
of inequalities, some of which serves as key instruments in tightening
the bounds and enhancing the precision of energy calculations within
graph structures. We utilize these tools to derive improved upper and
lower bounds on the pathway energy for graphs with suitable parameters.
Hutter et al. [13] explored
the use of machine learning to predict algorithm runtime based on
problem-specific features. A simulation of graphs for reduced order
modelling in city-scale district energy grids, leveraging spectral graph
theory, was recently proposed by Simonsson et al. [21]. Duraj and Mezic [9,15] introduced a novel complexity measure for
directed graphs, termed spectral complexity. The spectrum of the path
matrix, can be optimally resolved in polynomial time, despite the
inherent complexity of the graphs.
2. Motivation and methodology
Graph theory is fundamental in optimizing complex networks, yet
calculating pathway energy, key to measuring network connectivity
through vertex-disjoint paths-poses significant challenges. Efficient
computation of pathway energy is critical for designing robust and
high-performing networks. To address the complexity of calculating
pathway energy for intricate flower families, we propose a novel
algorithmic approach.
Our method constructs a matrix
that represents the maximum number of non-overlapping paths between
distinct vertex pairs. From the characteristic values of , we derive pathway energy bounds,
including upper, lower, improved upper, improved lower, and exact
limits. We further develop an algorithm that performs -trial analyses to assess the time
complexity of these graphs, by determining average, maximum, and minimum
execution times. This approach not only reveals computational challenges
across various graph configurations but also provides a streamlined
algorithmic framework. By combining advanced mathematical techniques
with innovative algorithms, our study offers new insights into network
complexity, significantly enhancing both theoretical understanding and
practical applications in graph theory.
3. Preliminaries
In this section, the ideas and inequalities that provide the
foundation for our work were discussed.
Definition 3.1. (Wheel) [16] A wheel graph is build by connecting each vertex of
a cycle to a single hub vertex.
This hub is referred to as the central vertex, and the cycle is termed the rim of .
Definition 3.2. (Helm) [16] A helm graph is a graph constructed by linking a
pendant edge to every vertex on the outer cycle of a wheel graph .
Definition 3.3. (Flower) [16] A flower graph is generated by connecting a
helm graph ’s pendent vertices
to its center vertex, denoted as .
Definition 3.4. (Sunflower graph) [8] A sunflower graph is constructed by transforming each
edge of the circumference of a wheel graph into a triangle. Two triangles are
connected by a common vertex if and only if their corresponding edges
are adjacent.
Definition 3.5. (Closed Sunflower graph) [4] When independent vertices of a sun flower
graph that are not contiguous
to its center vertex are joined, a closed sun flower graph is created, which causes a cycle to
occur on vertices.
Definition 3.6. (Blossom graph) [16] When all the vertices of a closed sun
flower graph are joined to
its center vertex, the resulting graph is called a blossom graph .
Theorem 3.7. (Cauchy-Schwarz inequality) [1,7,14] If and are real numbers, we
have
Theorem 3.8. (Arithmetic and Geometric mean
inequality(AM-GM))[1,7,14] Let be a number of vertex and and be the characteristic values.
Theorem 3.9. (Chebyshev’s Inequality (monotonic Condition)) [7] If and are non-decreasing, then: with the monotonicity condition from Chebyshev’s
Inequality.
Theorem 3.10. (Weighted AM–GM inequality) [7] Let , , and , , be
such that . Then
Theorem 3.11. (Weighted Cauchy–Schwarz inequality) [7] Let and for . Then: with
equality if and only if .
4. Deriving
the pathway energy boundaries on flower graphs families
The different pathway energy extremities such as lower, upper,
improved upper, and improved lower bounds for the flower graph families
are explored in this section.
Proposition 4.1. If
are the characteristic values of then,
Proof. Let us examine the vertex-disjoint pathway matrix
associated with a flower
graph. The elements of this matrix can be expressed in a structured
manner:
The following equation defines the characteristic
polynomial of this
square matrix: where the
characteristic values are denoted as . The
squared characteristic values added together can be expressed as
follows: Here denotes the sum of all the elements 4, 3
and 2 vertex-disjoint path matrix respectively.
4.1. The pathway
energy lower bounds for flower graph
Theorem 4.2. For a flower graph , , with vertices
and edges.
The lower bound of pathway energy is given by: where
are the weights, gives the total
sum of the characteristic value weights.
The improved lower bound of pathway energy is:
Proof. Consider the flower graph with an vertex-disjoint pathway
matrix of order , where
represents the vertices.
The characteristic values are obtained by solving the characteristic
polynomial .
The pathway energy is the
sum of the absolute values of the characteristic values of the
vertex-disjoint path matrix. The following condition describes this.
Moreover, this can also be written as the product of the absolute
characteristic value summations:
.
Case 1: Proof for the pathway energy lower bounds of
flower graph
From the Chebyshev’s Inequality 3, we derive that,
From the Weighted AM–GM inequality 4, we conclude,
Thus, the lower bounds of the pathway energy for flower graph is,
Case 2: Proof for the pathway energy improved lower
bounds.
From the AM-GM inequalities in Eq. (2), we derive that
Thus, the improved lower bounds of the pathway energy for flower
graph is,
Observation 4.3. The pathway energy of lower bounds, improved lower bounds and time
complexity analysis for
flower graphs with varying from 4
to 100 are computed and plotted in Figure 1: (a) and (b).
(a) The path energy bounds of flower
graphs(b) Algorithm execution time for flower
graphsFigure 1 The comparison of path energy bounds (a) and Time complexity execution (b) for ower graphs
4.2. The pathway
energy upper bound for flower graph
Theorem 4.4. For flower graph with ,
The upper bound of pathway energy is given by:
The improved upper bound of pathway energy is:
Proof. The methodology employed to ascertain the
characteristic values echoes that utilized in Theorem 4.2. Let denote the
characteristic values of the vertex-disjoint path matrix of .
Case 1: Proof for the pathway energy upper bound of
flower graph.
From the Cauchy-Schwarz inequality in the Eq. (1) we derive that,
To establish the upper bound, consider the expression , where the pathway energy is bounded by the
right-hand side. Substituting and
into the inequality yields the desired result.
Thus, the upper bound of the pathway energy of the flower graph
concluded by,
Case 2: Proof for the pathway energy improved upper
bound.
The Weighted Cauchy Schwarz inequality in (5) allows us to
deduce that,
For proving the improved upper bound, consider , such that the
pathway energy of the graph is less than RHS of the inequality, and
substituting
and , in the above
inequality,
Thus, the improved upper bound of the pathway energy for flower graph
is,
Observation 4.5. The pathway energy of upper bounds, improved upper bounds and time
complexity analysis for
flower graphs with varying from 4
to 100 are computed and plotted in Figure 1: (a) and (b).
5. The Pathway
energy boundaries on sunflower graph
The different pathway energy bounds of sunflower graph like lower, upper, improved lower,
and improved upper bounds are investigated in this section.
Proposition 5.1. The characteristic values of are if
are the characteristic values of .
Proof. The structure of the vertex-disjoint path matrix
for the sunflower graph
is depicted as follows,
The characteristic equation of this square matrix is given
by: where the characteristic
values are denoted as . The sum of
the squares of these characteristic values is defined as:
In this instance, denote the total of all elements 4, 3, and
2 respectively, present in the vertex-disjoint path matrices.
5.1. The pathway
energy lower bounds for sunflower graph
Theorem 5.2. For a sunflower graph with , there are vertices and
edges.
The lower bound of pathway energy is given by: where
are the weights, gives the total sum of the characteristic value
weights.
The improved lower bound of pathway energy is:
Proof. The proof is similar to Theorem 4.2 and is left to
the interest of the reader.
Observation 5.3. The pathway energy of lower bounds, improved lower bounds and time
complexity analysis for
sunflower graphs with order of
varying from 5 to 100 are shown in Figure 2: (a) and (b).
(a) The path energy bounds of sunflower
graphs(b) Algorithm execution time for sunflower
graphsFigure 2 The comparison of path energy bounds (a) and Time complexity execution (b) for sunower graphs
5.2. The pathway
energy upper bound for sunflower graph
Theorem 5.4. For sunflower graph with
,
The upper bound of pathway energy is given by:
The improved upper bound of pathway energy is:
Proof. The proof is similar to Theorem 4.4 and is left to
the interest of the reader.
Observation 5.5. The pathway energy of upper bounds, improved upper bounds and time
complexity analysis for
sunflower graphs with order of
varying from 5 to 100 are shown in Figure 2: (a) and (b).
6. The Path
energy bounds on closed sunflower graph
This section explicates the distinct path energy bounds for the
closed sunflower graph ,
comprising the lower, upper, exact energy, improved lower and upper
bound.
Proposition 6.1. If
are the characteristic values of then,
Proof. The arrangement of elements in the vertex-disjoint
path matrix of a closed
sunflower graph is shown below:
The characteristic equation associated with this square matrix is: where the characteristic values are
denoted as .
The squared sum of these characteristic values is expressed as, In this context, represent the
sums of all the elements 5 and 4 in the path matrices,
respectively.
6.1. The
path energy lower bound for the closed sunflower graph
Theorem 6.2. Let be a closed
sunflower graph comprising
vertices and edges.
The lower bound of pathway energy is given by, where is the weights of the characteristic
values and their sum is .
The improved pathway energy lower bound is given by,
Proof. The vertex-disjoint path matrix of the closed
sunflower network has order
, where the vertices are
represented by . Solving
the polynomial equation yields the characteristic values . Following
the method in Theorem 4.2 and using terminology that has already been
explained, the pathway energy is defined as the total of the
absolute values of these characteristic values.
.
Case 1: Proof for the pathway energy lower bound of
From the Chebyshev’s Inequality (3), we derive that,
From the Weighted AM–GM inequality (4), we conclude,
Thus, the lower bound is
Case 2: Proof for the pathway energy improved lower
bound.
From the AM-GM inequalities in Eq. (2), we derive
that
Thus, the improved lower bound of the pathway energy for closed
sunflower graph is,
Observation 6.3. The pathway energy of lower bounds, improved lower bounds and time
complexity analysis for
closed sunflower graphs with order of varying from 5 to 100 are depicted in
Figure 3: (a) and (b).
(a) The path energy bounds of closed
sunflower graphs(b) Algorithm execution time for closed
sunflower graphsFigure 3 The comparison of path energy bounds (a) and time complexity execution (b) for closed sunower graphs
6.2. The
exact pathway energy bound for closed sunflower graph
Theorem 6.4. For the closed sunflower graph , where , the exact bounds on the pathway
energy are as follows: corrected to two decimal places.
Proof. The vertex-disjoint path configuration of the graph is elaborated in detail in
the path adjacency matrix (6). It has roots, implying that it contains
characteristic values.
The characteristic equation of (6) is
Upon solving the Eq. (7), the characteristic values are determined
to be,
The Spectrum is expressed in the form of,
The exact closed sunflower graph pathway energy is given by,
The value occurs
times, repeated times, , and arrives once.
Therefore the pathway energy exact bound for closed sunflower graph
is denoted by
Observation 6.5. The pathway exact energy and time complexity analysis for closed sunflower graphs with
order of varying from 5 to 100
are shown in Figure 3: (a) and (b).
6.3. The path
energy upper bound for closed sunflower graph
Theorem 6.6. For Closed sunflower with
,
The upper bound of pathway energy is given by:
The improved upper bound of pathway energy is: .
Proof. In this segment to establish the upper bounds, follow
the approach of characteristic values determination in Theorem 4.2. For
the purpose of the proof, it is a essential to take into account the
following consideration,
Case 1: Proof for the pathway energy upper bound of
.
To establish the upper bound, apply the Cauchy-Schwarz inequality in
(1).
Consider , where the
pathway energy is bounded above. Substituting and into this inequality
yields the desired result.
Thus, the upper bound of the pathway energy of the closed sunflower
graph concluded by,
Case 2: Proof for the pathway energy improved upper
bound.
Using the Weighted Cauchy-Schwarz inequality from Eq. (5), we deduce the
improved upper bound: Substituting , , and in RHS gives the
result.
The improved upper bound of the path energy for the closed sunflower
graph is:
Observation 6.7.The pathway energy of upper bounds, improved upper bounds and time
complexity analysis for
closed sunflower graphs with order of varying from 5 to 100 are depicted in
Figure 3: (a) and (b).
Proof. The configuration of the vertex-disjoint path
adjacency matrix for a
blossom graph is outlined as follows, here
For this
matrix, the characteristic equation is, All the characteristic values are
represented by
The total of the squared characteristic values can be outlined as,
where and are specific terms related to
the matrix components.
7.1. The
pathway energy lower bound for the blossom graph
Theorem 7.2. Let be a blossom graph
comprising l= vertices and
edges.
The lower bounds of pathway energy is given by,
where are the weights, gives the total
sum of the characteristic value weights.
The improved pathway energy lower bound is given by,
Proof. In general, the blossom graph has a vertex-disjoint adjacency
matrix of order , with
the number of vertices denoted by . The characteristic values can be
determined by solving . As similar to the method earlier in Theorem 4.2, the pathway
energy , is the total of
the absolute values of these characteristic values.
Case 1: Proof for the pathway energy lower bound of
blossom graph
From the Chebyshev’s Inequality (3), we derive that,
We derive the following from the Weighted AM–GM inequality (4):
Thus, the lower bound of the pathway energy for blossom graph is,
Case (ii): Proof for the pathway energy improved
lower bound.
We obtain that from the AM-GM inequality in Eq. (2).
Thus, the improved lower bound of the pathway energy for blossom
graph is,
Observation 7.3. The pathway energy of lower bounds, improved lower bounds and time
complexity analysis for
blossom graphs with order of
varying from 5 to 100 are plotted in Figure 4: (a) and (b).
(a) The path energy bounds of blossom
graphs(b)Algorithm execution time for blossom
graphsFigure 4 The comparison of path energy bounds (a) and time complexity execution (b) for blossom graphs
7.2. The pathway
energy exact bound for blossom graph
Theorem 7.4. The defined bounds for the pathway energy in the blossom graph , under the condition that , are .
Proof. The Eq. (8) provides a detailed description of the
pathway configuration for the vertex-disjoint matrix of the blossom
graph. Solving the characteristic equation
derives the characteristic
values in this way: .
The spectrum can be articulated as: = .
The exact energy path of the blossom graph provided by, The term appears times, while
appears once. Consequently,
the exact pathway energy bound for the blossom graph is given by:
Observation 7.5. The exact path energy and time complexity analysis for blossom graphs with varying from 5 to 100 are plotted in
Figure 4: (a) and (b).
7.3. The pathway
energy upper bound for blossom graph
Theorem 7.6. For blossom graph with
,
The upper bound of pathway energy is given by:
The improved upper bound of pathway energy is: .
Proof. This section of the proof establishes the upper
bounds using an analogous method of determining characteristic values as
in Theorem 4.2.
Case 1: Proof for the path energy upper bound of
blossom graph.
For deriving the upper bound Cauchy-Schwarz Inequality (1) leads that, , where the pathway energy is constrained by
the right-hand side. Substituting and
leads to the desired conclusion,
Thus, the upper bounds of the pathway energy of the blossom graph
concluded by Case 2: Proof for the pathway
energy improved upper bound.
The Weighted Cauchy Schwarz inequality 5 allows us to deduce
that,
By substituting ,
and , in the above inequality,
Thus, the improved upper bound of the pathway energy for blossom
graph is,
Observation 7.7. The pathway energy of upper bounds, improved upper bounds and time
complexity analysis for
blossom graphs with order of
varying from 5 to 100 are plotted in Figure 4: (a) and (b).
8. Complexity analysis of
flower families
We undertook a comprehensive computational analysis of flower
families, employing algorithmic techniques to quantify the energy of
these graphs alongside the time taken for each calculation. By plotting
energy against computation time, we meticulously assessed the complexity
and efficiency inherent in each graph type. Our results reveal that
sunflower graphs exhibit a significantly higher complexity compared to
the flower families under investigation. Notably, the computational time
for sunflower graphs adheres to a complexity of , underscoring its critical nature
in relation to the flower families discussed in this study.
Figure 5 Analysis of time complexity of flower
families
9. Conclusion
This paper presents an innovative algorithmic framework for analyzing
pathway energy within flower families, encompassing a wide range of
graph types. We established precise limits for pathway energies and
conducted an in-depth analysis of time complexity, illuminating
significant computational challenges in this domain. The hallmark of our
work is the enhanced efficiency and versatility of our pathway energy
calculations, providing a robust tool for addressing complex spectral
graph problems. These findings pave the way for future research focused
on optimizing algorithms and exploring new classes of graphs. Moreover,
this research has substantial practical implications for network
optimization, improving algorithmic efficiency, and advancing spectral
graph theory. Ultimately, our contributions propel the progress of
computational graph theory and its related fields.
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