1. Introduction
The theory of inequalities plays an important role in studying a diverse range of problems in nonlinear analysis, including differential equations, optimization, operational research and numerical error analysis. Based on their significance, researchers have extensively studied and extended them for higher dimensions and function classes to eliminate the shortcomings of classical counterparts. In the exponential growth of inequalities, the role of convexity is unparalleled. A central theme of this theory is the Hermite–Hadamard inequality, which is closely related to convex analysis and numerical integration. Many refinements and extensions of it have been achieved under various convexity and differentiability assumptions; see [
1,
2,
3].
Integral inequalities provide fundamental tools for deriving analytical estimates and approximation errors. In the following perspective, Dragomir et al. [
4] introduced Simpson-type inequalities under the bounded-variation and Lipschitz conditions. Later on, Shuang and his coauthors obtained three-point inequalities for
convex functions in [
5]. Cheng obtained a class of Ostrowski–Grüss-type estimates in [
6]. Liu derived the error bounds for higher order differentiable functions for three-point closed formulas in [
7]. Acu et al. [
8] and Yang and Tseng [
9] further contributed to the analysis of the numerical integration methods and approximation inequalities, respectively, while Delavar et al. [
10] delivered the weighted Simpson-type inequalities under convexity assumptions. Alomari [
11] studied approximation inequalities for the Milne quadrature formula. Javed et al. [
12,
13] studied classical approximation inequalities along with their applications based on a generic identity and upper bounds for the remainder term of Boole’s quadrature rule.
Fractional calculus is one of the most active fields of mathematical analysis, and involves the generalization of the classical notions of differentiation and integration to real (and complex) orders, and a natural language for describing memory-dependent and hereditary phenomena occurring in all fields of physics, engineering and applied sciences [
14]. One of the important directions where this theory has proven fruitful is the study of integral inequalities which are used in the estimation of integrals, in the control of approximation errors and in the analysis of the solution of differential and integral equations.
The fractional Chebyshev inequalities were studied in [
15] by Belarbi and Dahmani and the fractional framework was extended to Minkowski-type inequalities in [
16]. The Hadamard inequality and its right estimates using
fractional and generalized operators were discussed in [
17,
18]. Later on, Mohsen et al. [
19] extended the left Hadamard inequality for
-fractional operators. Mateen et al. [
20] applied the fractional concepts to explore Weddle-type inequalities. The incorporation of weight functions into fractional inequalities enables the approximation of weighted fractional integrals. Almoneef et al. [
21] obtained weighted Newton-type inequalities for various classes of functions via
integrals, while the weighted fractional Euler–Maclaurin inequalities for convex and bounded-variation functions were examined in [
22,
23].
In parallel, powerful computational tools have emerged for the validation of analysis-based theoretical estimates: neural networks approximate highly nonlinear relationships present in fractional operators [
24], deep learning frameworks solve forward and inverse problems for differential and integral equations [
25], and fractional physics-informed neural networks embed fractional operators directly into their learning architecture [
26]. Recently, an artificial neural network was used to predict the left, middle and right sides of fractional Bullen-type inequalities with strong agreement against analytical results [
27]. Symbolic Regression [
28] and extreme gradient boosting (XGBoost) [
29] have proven highly effective for learning strong nonlinearities in tabular regression, together creating a fertile link between analytical mathematics and computational intelligence.
Motivated by recent contributions in weighted inequalities, the present work introduces a new class of weighted fractional Boole-type inequalities involving the fractional integral operator and symmetric weight functions. To derive the main inequalities, a weighted fractional identity that establishes a natural correspondence between classical Boole-type quadrature structures and fractional integral operators will be developed. Under assumptions of s-convexity, boundedness, Lipschitz continuity and bounded variation, several inequalities are derived that provide meaningful error bounds under weaker hypotheses than those required by classical Boole estimates, where a sixth derivative regularity is assumed. The fractional parameter and symmetric weight function endow important flexibility, recover several known inequalities as special cases, and unify existing results. Also, we will discuss some interesting special cases for different choices of weights relating to renowned classes of integrals. In parallel with these analytical results, a theorem-consistent computational framework is developed over 5400 samples using Symbolic Regression, XGBoost and SHAP (SHapley Additive exPlanations) analysis to investigate the contribution of input features that predicts exactly that the is less than the of the fractional inequality.
Our proposed results are novel due to their generic nature. They unify the fractional and classical inequalities for a diverse range of function classes using symmetric weight functions. Moreover, for , we get weighted Boole-type inequalities under convexity assumptions, which are also new in the literature. The weighted fractional inequalities enable us to discuss the error analysis of Boole’s rule for special kinds of integrals like logarithm-, Jacobi-, and Chebyshev-type integrals. The computational analysis via machine learning techniques is another fascinating part. It focuses on the validation and analysis of all contributors utilizing the technique of SHAP. This is the first study where the comparison of different machine learning techniques for inequalities has been presented.
The current study is structured as follows:
Section 2 contains essential notions, classical inequalities, and fractional integral operators required for the derivation of the main results;
Section 3 offers the primary outcomes with numerical examples and applications;
Section 5 provides the computational analysis via two machine learning techniques; while
Section 6 concludes the study and indicates directions for future research.
2. Preliminaries
In the following sections the basic definitions, classical inequalities and fractional integral operators will be gathered as a basis for the subsequent analysis.
Definition 1 ([
1])
. A function is said to be convex if The theory of integral inequalities is closely related to the concept of convexity which offers the geometric framework of numerous classical estimates. One of the most important results in this direction is the Hermite–Hadamard inequality, which gives two-sided bounds for the integral mean of a convex function in terms of its values at the midpoint and the endpoints and it is stated as shown below.
Theorem 1
([
1])
. For a convex function , the following inequality holds Next, we provide the definition of s-convex functions.
Definition 2
([
1])
. A function is said to be s-convex if The Euler Gamma function is defined as follows.
Definition 3.
For the Euler Gamma function is defined as The left-sided and right-sided
fractional integrals are defined in [
14] as follows.
Definition 4.
Let and let . The left-sided and right-sided fractional integrals of Ψ are defined byand Boole’s rule is a particular five-point Newton–Cotes quadrature formula which is exact for all polynomials of a degree of at most 4. It is given by
The classical error estimate was introduced by Philip J. Davis and Philip Rabinowitz in
Methods of Numerical Integration [
30] and is stated as follows.
Theorem 2.
Let be a six-times continuously differentiable function on such thatThen This estimate indicates that the classical form of Boole’s rule is highly accurate, and shows that the classical form is significantly linked to strong smoothness assumptions. As a consequence, numerous subsequent investigations have tried to obtain Boole-type inequalities under weaker smoothness assumptions. These extensions can be very useful when the function is not six-times differentiable.
The second result is a Boole-type inequality where convexity conditions have been imposed on the absolute value of the first derivative.
Theorem 3
([
13])
. Let be a continuously differentiable function. If is convex on , then 5. Numerical Experiments and Machine Learning Validation
Solving the fractional integral inequalities analytically for different values of fractional order is very difficult, except for some simple polynomial functions. To resolve this problem and to reduce the computational cost, we have used machine learning techniques. This section provides a computational study that complements the analytical development of Theorem 4 and illustrates the practical application of the proposed framework. The study has two main goals: first, to numerically verify the validity of the weighted fractional Boole-type inequality for a large class of parameters and function classes, and second, to develop data-driven models for predicting the exact of the inequality.
The computational framework consists of three steps: mathematical formulation, numerical evaluation, and data-driven modeling, as shown in
Figure 3. During the first stage the analytical quantities corresponding to the inequality are checked over a family of strictly convex test functions, and the inequality is tested sample-wise. In the second stage, we use two complementary learning paradigms to approximate the nonlinear structure of the exact fractional Boole-type expression: Symbolic Regression, which is known for its interpretability and ability to generate explicit closed-form approximation solutions, and XGBoost, which is known for its high accuracy when applied to nonlinear tabular data.
The computational study uses a synthetic dataset of 5400 valid samples described directly from the proposed weighted fractional Boole-type inequality framework. Each sample is determined by random sampling of the interval endpoints
and
(
), random sampling of the fractional order
and selection of one of six convex benchmark functions by a function identifier. The benchmark functions
are carefully selected to cover exponential and hyperbolic growth and the inequality is studied across a variety of nonlinear growth. The numerical values of the exact
and the upper bound
given in Theorem 4 are evaluated for each of the generated samples. The sampling parameters, the evaluation of the endpoint and midpoint function values, the evaluation of the endpoint derivatives, the transformed interval quantities, and the fractional integral components are recorded in the dataset. The exact
is kept, and the
and the slack variable
are stored as auxiliary quantities used for theorem validation. There are 17 variables out of a total of 20 variables that are registered and used as predictors for the ML models.
Table 2 and
Table 3 provide a summary of the structure of the dataset and the representation of features.
The resulting dataset is first numerically validated against Theorem 4. The condition
, called admissibility, is checked for each pair that is computed. The results show that the inequality holds for all 5400 generated samples. The global validation is shown in
Figure 4. All sampled points lie on or above the diagonal line
, which shows that the numerical consistency and robustness of the proposed bound is maintained throughout the computational domain.
The behaviour of the exact
and analytical
is investigated for different values of
to understand the sensitivity of the inequality to the fractional integration order for each of the six convex test functions, as shown in
Figure 5. In all cases, the inequality holds for all admissible values of
, while the variation and size of both sides depend on the nonlinear growth of the function. The higher-order derivative behaviour gives the bound a greater tightness, with rapidly growing functions like
and
having significantly larger ranges and dispersions than the more moderate functions like
and
.
The tightness and stability of the proposed bound are quantified using the slack variable. A non-negative slack over all the samples is equivalent to the global satisfaction of the inequality, whereas the distribution of the slack gives an indication of how conservative the bound is for each function class. The empirical distributions of the slack are given in
Figure 6.
After the numerical correctness of the inequality has been established, the focus shifts to the predictive modeling of the exact
and
, which are regarded as the regression targets noted as
y. The data is divided into a training set and a test set in
ratios, with 17 predictor variables listed in
Table 3. They are used as inputs to the model. Symbolic Regression performs a search over the space of analytical expressions in order to discover a closed-form approximation to the
,
, that optimizes a dynamic trade-off between accuracy and structural complexity, thereby revealing explicitly the dependence of the
on the underlying variables. In contrast, XGBoost builds an additive ensemble of regression trees,
where
is the space of regression trees and
K is the number of boosting rounds, with each successive tree being fit to the residual of the previous ones. The additive structure in this model makes it stage-wise, which makes Symbolic Regression particularly suited to fit the strong nonlinearity in the fractional Boole-type expression.
The performance of the models is evaluated using the Root Mean Squared Error (RMSE), the Mean Absolute Error (MAE) and coefficient of determination
, as given below:
where
is the desired target and
is the predicted target,
is the mean of the observed targets, and
n is the number of samples. Lower RMSE and MAE values indicate better accuracy and an
value closer to one indicates stronger correspondence between the prediction and observation. Five-fold cross-validation is also performed to check the generalization ability of the boosting model.
Table 4 and
Table 5 report the quantitative performance of both models on the held-out test set. While each model successfully captures the nonlinear behaviour of the weighted fractional Boole-type expression, Symbolic Regression outperforms XGBoost across all evaluation metrics. For
, Symbolic Regression attains
with RMSE and MAE values of
and
, compared with
, RMSE
, and MAE
for XGBoost. Also for
, Symbolic Regression attains
with RMSE and MAE values of
and
, compared with
, RMSE
, and MAE
for XGBoost. The slack distribution for Symbolic Regression attains
with RMSE and MAE values of
and
, compared with
, RMSE
, and MAE
for XGBoost, which confirms the strong generalization ability of the Symbolic Regression.
These error metrics are compared in
Figure 7 and
Figure 8. The RMSE–MAE comparison shows a significant improvement in prediction error when using Symbolic Regression and the
comparison shows that the Symbolic Regression model closely agrees with the exact value.
The comparisons between the approximated and exact values of the
and
of Theorem 4 for all six test functions are presented in
Figure 9. Clearly, the result is validated through line graphs using exact and approximated values through Symbolic Regression.
Figure 10 and
Figure 11 further illustrate the validity of the
and
of Theorem 4 for all admissible functions using exact and XGBoost approximations.
The error histograms of both sides across all test functions using XGboost approximations with log transformation of residues and counts on the horizontal and vertical axis, respectively, are given in
Figure 12. Most of the residues are centered around zero for all functions.
SHAP is a widely employed technique to assess the impact of each contributor on the prediction process following the game theory. Mainly, it splits the credit of each prediction over all features. Moreover it provides detailed information about the local and global behaviour of input variables. The mathematical formulation is given in [
34] as:
where
,
and
are the predicted value of
ith sample, average SHAP value, and SHAP value
jth contributor in the
ith sample, respectively.
The SHAP waterfall analyses of both the
and
are presented in
Figure 13 and
Figure 14. One can observe that the most effective contributor is the right endpoint
. But the behaviour is slightly different for all under-consideration functions.
Now we discuss the global analysis of major contributors for all functions for both the
and
in
Figure 15 and
Figure 16, respectively. The role of the right endpoint is very crucial to predict any value, while the fractional order produces minimal changes as compared with
.
The SHAP feature importance in a controlled environment across all test functions for the
and
is discussed in
Figure 17 and
Figure 18, respectively. These visuals are the straightforward verification of global SHAP analysis.
6. Conclusions
In this study, a new class of weighted fractional Boole-type inequalities based on the fractional integral operator and symmetric weight functions has been introduced. By using the newly derived weighted fractional identity instead of the classical sixth-derivative error estimate, several inequalities were derived under convexity, s-convexity, boundedness, Lipschitz continuity and bounded-variation assumptions, which is a relaxation of the strong smoothness requirements on the classical formulation. The flexibility of the proposed method can be seen from the fact that for suitable choices of the fractional parameter and weight function, the inequalities generalize several known inequalities as special cases. The applications to special means and to a composite weighted quadrature rule, along with the examples and graphical illustrations, further highlight the analytical and practical relevance of the results.
This theoretical study was conducted using 5400 samples obtained from the proposed inequality to verify the theoretical framework. For each sample the bound was satisfied, and the slack variable was non-negative throughout the entire computation domain, thus verifying that the proposed estimate is consistent and stable for various choices of parameters and functions. In terms of modeling, Symbolic Regression provided the interpretable closed-form approximation to the theorem while being able to make predictions close to 1. All these findings are brought together within a single scalable framework, linking fractional calculus, numerical approximation and explainable artificial intelligence. Several directions exist for future research: an extension of these types of inequalities to other generalized fractional operators including Atangana–Baleanu fractional operators, a wider class of weight functions, and higher order quadrature structures, and applying other techniques of computational intelligence to the analysis and prediction of related fractional integral inequalities. In future, the proposed inequalities can be explored for a wide range of other fractional operators and generalized classes of convexity. Also, a good problem to investigate is the weighted Boole-type inequalities of higher order differentiable functions. One can transform the proposed framework into a discrete structure using quantum calculus. One can discuss the coordinated weighted Boole-type inequalities under different assumptions. Our next target is to develop an ML-based calculator for fractional inequalities to approximate the bounds for any admissible functions to reduce the computational cost. Hopefully, the machine learning techniques involved in this study will play a crucial role in the computational analysis of inequalities.