1. Introduction
In 1995, Heinig and Maligranda [
1] proved that if
is decreasing on
and
is increasing on
with
then for any
The inequality (
1) is reversed when
In addition, the authors of [
1] proved that if
is increasing on
and
is decreasing on
with
then for any
We define that if implies with then is C-decreasing and if implies then is C-increasing. We observe that for the 1-decreasing function is the normal decreasing function and the 1-increasing function is the normal increasing function.
By using the definition of
C-monotonic functions, Pečarić et al. [
2] generalized (
1) and (
2) for
C-monotone functions with
they proved that if
is
C-decreasing on
for
and
is increasing and differentiable on
such that
then
In addition, they proved that if
is
C-increasing on
for
and
is increasing and differentiable on
such that
, then
The authors of [
2] proved that if
is
C-increasing on
with
and
is decreasing and differentiable on
such that
, then
and they also proved that if
is
C-decreasing on
for
and
is decreasing and differentiable on
such that
, then
In the last decades, some authors have been interested in finding some discrete results on
analogues to
-bounds in different fields in analysis and, as a result, this subject becomes a topic of ongoing research. One reason for this upsurge of interest in the discrete case is also due to the fact that discrete operators may even behave differently from their continuous counterparts. In this paper, we obtain the discrete inequalities as special cases of the results with a general domain called the time scale
. The time scale
is an arbitrary nonempty closed subset of the real numbers
. These results contain the classical continuous and discrete inequalities as special cases when
and
and can be extended to different inequalities on different time scales such as
,
,
for
, etc. In recent years, the study of dynamic inequalities on time scales has received a lot of attention and become a major field in pure and applied mathematics. For more details about the dynamic inequalities on time scales, we refer the reader to the papers [
3,
4,
5,
6,
7,
8,
9,
10,
11,
12,
13,
14,
15,
16]. For example, Saker et al. [
17] proved some dynamic inequalities for
C-monotonic functions and proved that if
is
C-decreasing on
with
and
is increasing on
such that
then
and if
is
C-increasing on
for
and
is increasing on
such that
then
In addition, they proved that if
is
C-increasing on
with
and
is decreasing on
such that
then
and if
is
C-decreasing on
with
and
is decreasing on
such that
then
Our aim in this paper is to generalize the inequalities (
1)–(
6) on time scales by establishing some new dynamic inequalities involving
C-monotonic functions.
The paper is organized as follows. In
Section 2, we present some preliminaries concerning the theory of time scales and the definitions of
C-monotonic functions. In
Section 3, we prove the main results using the chain rule on time scales and the properties of
C-monotonic functions. Our results when
give the inequalities (
1)–(
6) proved by Heinig, Maligranda, Pečarić, Perić and Persson, respectively. Our results for
are essentially new.
2. Preliminaries and Basic Lemmas
In this section, we recall the following concepts related to the notion of time scales. A time scale
is an arbitrary nonempty closed subset of the real numbers
. For more details of time scale analysis, we refer the reader to the two books by Bohner and Peterson [
18,
19] which summarize and organize much of the time scale calculus. We define the time scale interval
by
. A function
→
is said to be right-dense continuous (rd-continuous) provided that
is continuous at right-dense points and at left-dense points in
, left-hand limits exist and are finite. The set of all such rd-continuous functions is denoted by
The product and quotient rules for the derivative of the product
and the quotient
of two differentiable functions
and
are given by
Let
be continuously differentiable and suppose that
is delta-differentiable. Then,
is delta-differentiable and there exists
in the real interval
with
In addition, the formula
holds. A special case of (
7) is
In this paper, we will refer to the (delta) integral which we can define as follows. If
, then the Cauchy (delta) integral of
is defined by
It can be shown (see [
18]) that if
then the Cauchy integral
exists,
and satisfies
. The integration on discrete time scales is defined by
In case
, we have
and in case
, we have
The integration by parts formula on time scale is given by
In addition, we have for
and
that
Definition 1. Assume that is a time scale and If implies then ω is decreasing and if implies then ω is increasing.
We can generalize the definition of the increasing and decreasing function to be C-increasing and C-decreasing, respectively, which is given in the following.
Definition 2 ([
17])
. Assume that is a time scale, and If implies then ω is C-decreasing. If implies then ω is C-increasing.As a special case, when we observe that the 1-decreasing function is decreasing and the 1-increasing function is increasing.
Lemma 1. Let If ω is C-decreasing for , then is -decreasing and if ϖ is C-increasing, then is -increasing.
Proof. Since
is
C-decreasing, we have for
that
, and then, we obtain (where
) that
Thus,
is
-decreasing.
Since
is
C-increasing, we have for
that
and then, we see (where
) that
which indicates that
is
-increasing. The proof is completed. □
3. Main Results
Throughout the paper, we assume that the functions (without mentioning) are rd-continuous nonnegative and -differentiable functions, locally -integrable on , and the considered integrals are assumed to exist.
In this section, we state and prove our main results.
Theorem 1. Assume that is a time scale with , and Furthermore, assume that if χ is -decreasing on and λ is increasing on such that Ifthen Proof. Since
is an increasing function with
and
is
-decreasing function, we have for
that
and then,
and then,
By applying chain rule formula on the term
we have for
that
Again, by applying the chain rule formula on the term
we obtain
where
From (
12), we observe that
Substituting (
13) and (
14) into (
15), we get
Since
and
is an increasing function, then
Substituting (
17) into (
16), we observe that
Substituting (
11) into (
18), we get
By using (
8) and
is an increasing function, we have from (
19) that
and then, the function
is increasing on
Since
is an increasing function, we have for
that
and then (note that
),
which is the desired inequality (
9). The proof is completed. □
Corollary 1. When , we observe that (8) holds already with equality and we get the inequality (1) proved by Heinig and Maligranda [
1].
As a special case of Theorem 1, when such that and , we have the following corollary.
Corollary 2. Assume that ω is C-decreasing on and ϖ is increasing on such that Ifthen Corollary 3. In Corollary 2, when , we observe that (20) holds with equality and then we obtain the inequality (3) proved by Pečarić et al. [
2].
Corollary 4. In Corollary 2, when , we have that if ω is C-decreasing sequence for and ϖ is increasing with such thatthen Theorem 2. Assume that is a time scale with , and Furthermore assume that χ is -increasing on with and λ is increasing on such that Ifthen Proof. Since
is an increasing function with
and
is a
-increasing function, we have for
that
and thus,
and then,
By applying the chain rule formula on the term
we have for
that
Again, by applying the chain rule formula on the terms
we obtain
where
From (
26), we observe that
Substituting (
27) and (
28) into (
29), we get
Since
and
is an increasing function, then
Substituting (
31) into (
30), we see that
Substituting (
25) into (
32), we get
By using (
22) and
is an increasing function, the inequality (
33) becomes
and then, the function
is decreasing on
Since
is a decreasing function, then we have for
that
and then (note that
),
which is the desired inequality (
23). The proof is completed. □
As a special case of Theorem 2, when such that and , we get the following corollary.
Corollary 5. Assume that is a time scale with and Furthermore, if ω is C-increasing on for and ϖ is increasing on with such thatthen Corollary 6. As a special case of Corollary 5, when we have that (34) holds already with equality and we get the inequality (4) proved by Pečarić et al. [
2].
Corollary 7. In Corollary 5, when we have that if ω is a C-increasing sequence for and ϖ is increasing with such thatthen Theorem 3. Assume that is a time scale with , and Furthermore, if χ is -increasing on and λ is decreasing on with such thatthen Proof. Since
is a decreasing function with
and
is a
-increasing function, we have for
that
and thus,
By applying the chain rule formula on the term
we have for
that
Again by applying the chain rule formula on the terms
we obtain
where
From (
38), we observe that
Substituting (
39) and (
40) into (
41), we get
Since
and
is a decreasing function, then
Substituting (
43) into (
42), we see that
Substituting (
37) into (
44), we get
By using (
35) and
is a decreasing function, we have from (
45) that
and then, the function
is decreasing on
Since
is a decreasing function, we have for
that
and then (note that
),
which is the desired inequality (
36). The proof is completed. □
Corollary 8. As a special case of Theorem 3, when and we observe that (35) holds with equality, and then, we get the inequality (2) proved by Heinig and Maligranda [
1].
As a special case of Theorem 3, when such that and , we get the following corollary.
Corollary 9. If ω is C-increasing on and ϖ is decreasing on with such thatthen Corollary 10. As a special case of Corollary 9, when we observe that (46) holds already with equality and we get the inequality (5) proved by Pečarić et al. [
2].
Corollary 11. In Corollary 9, when we have that if ω is C-increasing sequence for and ϖ is decreasing with such thatthen Theorem 4. Assume that is a time scale with , and Furthermore, if χ is -decreasing on and λ is decreasing on with such thatthen Proof. Since
is a decreasing function with
and
is a
-decreasing function, we have for
that
and then,
By applying the chain rule formula on the term
we have for
that
Again, by applying the chain rule formula on the terms
we obtain
where
From (
50), we observe that
Substituting (
51) and (
52) into (
53), we get
Since
and
is a decreasing function, we obtain
Substituting (
55) into (
54), we observe that
Substituting (
49) into (
56), we get
By using (
47) and
is a decreasing function, we have from (
57) that
and then, the function
is increasing on
Since
is an increasing function, we have for
that
and then (note that
),
which is the desired inequality (
48). The proof is completed. □
As a special case of Theorem 4, when such that and , we get the following corollary.
Corollary 12. Assume that is a time scale with and Furthermore, if ω is C-decreasing on and ϖ is decreasing on with such thatthen Corollary 13. As a special case of Corollary 12, when we have that (58) holds already with equality and we also get the inequality (6) proved by Pečarić et al. [
2].
Corollary 14. In Corollary 12, when we have that if ω is a C-decreasing sequence for and ϖ is decreasing with such thatthen 4. Conclusions and Future Work
In this paper, we establish some new dynamic inequalities involving C-monotonic functions with on time scales. It is known that if then the 1-decreasing function is decreasing and the 1-increasing function increasing. Thus, our results are special cases when and give the inequalities involving increasing or decreasing functions. These results can be proved by applying the properties of C-monotonic functions and the chain rule formula on time scales. In the future, we hope to study the dynamic inequalities involving C-monotonic functions via conformable delta fractional calculus on time scales.
Author Contributions
Software and writing—original draft, M.Z., G.A., A.I.S. and A.M.H.; writing—review and editing C.C., H.M.R. and M.Z. All authors have read and agreed to the published version of the manuscript.
Funding
Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia.
Data Availability Statement
Not applicable.
Acknowledgments
Princess Nourah bint Abdulrahman University Researchers Supporting Project number (PNURSP2022R45), Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia.
Conflicts of Interest
The authors declare no conflict of interest.
References
- Heinig, H.; Maligranda, L. Weighted inequalities for monotone and concave functions. Stud. Math. 1995, 116, 133–165. [Google Scholar]
- Pećarić, J.; Perixcx, I.; Persson, L.E. Integral inequalities for monotone functions. J. Math. Anal. Appl. 1997, 215, 235–251. [Google Scholar] [CrossRef] [Green Version]
- AlNemer, G.; Saied, A.I.; Zakarya, M.; El-Hamid, H.A.A.; Bazighifan, O.; Rezk, H.M. Some New Reverse Hilbert’s Inequalities on Time Scales. Symmetry 2021, 13, 2431. [Google Scholar] [CrossRef]
- Bibi, R.; Bohner, M.; Pećarić, J.; Varošanec, S. Minkowski and Beckenbach-Dresher inequalities and functionals on time scales. J. Math. Inequal 2013, 7, 299–312. [Google Scholar] [CrossRef] [Green Version]
- Bohner, M.; Nosheen, A.; Pećarić, J.; Younis, A. Some dynamic Hardy-type inequalities with general kernels. Math. Ineq. Appl. 2014, 8, 185–199. [Google Scholar] [CrossRef] [Green Version]
- Bohner, M.; Georgiev, S.G. Multiple integration on time scales. In Multivariable Dynamic Calculus on Time Scales; Springer: Cham, Switzerland, 2016; pp. 449–515. [Google Scholar]
- Donchev, T.; Nosheen, A.; Pećarić, J.E. Hardy-type inequalities on time scales via convexity in several variables. ISRN Math. Anal. 2013, 2013, 1–9. [Google Scholar] [CrossRef] [Green Version]
- Fabelurin, O.O.; Oguntuase, J.A. Multivariat Hardy—Type inequalities on time scales via superquadraticity. Proc. A. Razm. Math. Inst. 2015, 167, 29–42. [Google Scholar]
- El-Deeb, A.A.; Elsennary, H.A.; Cheung, W. Some reverse Hölder inequalities with Specht’s ratio on time scales. J. Nonlinear Sci. Appl. 2018, 11, 444–455. [Google Scholar] [CrossRef]
- Oguntuase, J.A.; Persson, L.E. Time scales Hardy-type inequalities via superquadracity. Ann. Funct. Anal. 2014, 5, 61–73. [Google Scholar] [CrossRef]
- Řehak, P. Hardy inequality on time scales and its application to half-linear dynamic equations. J. Inequalities Appl. 2005, 2005, 495–507. [Google Scholar] [CrossRef] [Green Version]
- Rezk, H.M.; AlNemer, G.; Saied, A.I.; Bazighifan, O.; Zakarya, M. Some New Generalizations of Reverse Hilbert-Type Inequalities on Time Scales. Symmetry 2022, 14, 750. [Google Scholar] [CrossRef]
- Rezk, H.M.; Saied, A.I.; AlNemer, G.; Zakarya, M. On Hardy–Knopp Type Inequalities with Kernels via Time Scale Calculus. J. Math. 2022, 2022, 1–13. [Google Scholar] [CrossRef]
- Saker, S.H.; Saied, A.I.; Krnić, M. Some new dynamic Hardy-type inequalities with kernels involving monotone functions. Rev. Real Acad. Cienc. Exactas Fis. Nat. Ser. A. Mat. 2020, 114, 1–16. [Google Scholar] [CrossRef]
- Saker, S.H.; Saied, A.I.; Krnić, M. Some New Weighted Dynamic Inequalities for Monotone Functions Involving Kernels. Mediterr. Math. 2020, 17, 1–18. [Google Scholar] [CrossRef]
- Wong, F.H.; Yeh, C.C.; Yu, S.L.; Hong, C.H. Young’s inequality and related results on time scales. Appl. Math. Lett. 2005, 18, 983–988. [Google Scholar] [CrossRef]
- Saker, S.H.; Awwad, E.; Saied, A.I. Some new dynamic inequalities involving monotonic functions on time scales. J. Funct. Spaces 2019, 2019, 1–11. [Google Scholar] [CrossRef]
- Bohner, M.; Peterson, A. Dynamic Equations on Time Scales: An Introduction with Applications; Birkhäuser: Boston, MA, USA, 2001. [Google Scholar]
- Bohner, M.; Peterson, A. Advances in Dynamic Equations on Time Scales; Springer Science & Business Media: New York, NY, USA, 2002. [Google Scholar]
| Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. |
© 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).