Abstract
In this article, using a (,a)-nabla conformable integral on time scales, we study several novel Hilbert-type dynamic inequalities via nabla time scales calculus. Our results generalize various inequalities on time scales, unifying and extending several discrete inequalities and their corresponding continuous analogues. We say that symmetry plays an essential role in determining the correct methods with which to solve dynamic inequalities.
1. Introduction
Hardy [1] proved the classical discrete double series inequality of the Hilbert type: If and and then we have
Unless all the sequence or is null. Hardy also established the following integral analogous of the inequality (1):
Unless or where and g are measurable non-negative functions, such that and and , with the best constant , in (1) and (2).
In [2], Pachpatte established the following Hilbert-type integral inequalities under the following conditions: If and for and where and are positive real numbers and define and for and and , are two real-valued non-negative, convex, and submultiplicative functions defined on , then
and
where
and
For more results on Hilbert-type inequalities and other, please see [3,4,5,6]. See also [7,8,9,10,11,12,13]. As we know that time scale is an arbitrary, non-empty closed subset of the set of real numbers , and the jump operators, forward and backward, are defined by , . For more details, see [7]. The following relations are used.
- (i)
- For , then
- (ii)
- For , then
For more details on the conformable nabla calculus, see [3].
We suppose that denotes the set of all -continuous functions in and and is the set of all functions in for which both the first partial derivative and the first partial derivative exist in . Similarly, we can define .
In order to obtain our result in this paper, we need the following lemmas.
Lemma 1
(Reversed Dynamic Hölder’s Inequality). Suppose with Assume be integrable functions and with , then
Proof.
This lemma is a direct extension of the (Lemma 9, [14]). □
Lemma 2
(Reversed Dynamic Jensen’s inequality). Let r, and If and is concave, then
Proof.
This lemma is a direct extension of the (Lemma 10, [14]). □
Definition 1.
Φ is called a supermultiplicative function on if
In this paper, we establish a (,a)-nabla conformable integral inequality of Hardy–Hilbert type on a time scale. In special cases, we will recover some dynamic continuous and discrete inequalities known in the literature. Symmetry plays an essential role in determining the correct methods with which to solve dynamic inequalities.
Now, our main results will be presented.
2. Main Results
First, we suppose the following assumptions:
- be time scales with
- are non-negative, nabla integrable functions defined as
- have partial - derivatives and with respect to and , respectively.
- All functions used in this section are integrable according to sense.
- are n positive nabla-integrable functions defined for
- and are positive nabla-integrable functions defined for
- and , are n real-valued, non-negative concave and supermultiplicative functions defined on
- and are positive real numbers.
- and
- and
- is a positive real number.
- are n positive functions.
The first important inequality is stated in the following theorem:
Theorem 1.
Let , and be satisfied. Then, for and , we find that
where
Proof.
From the hypotheses of Theorem 1, and it is easy to observe that
Using inverse Jensen dynamic inequality, we obtain that
Applying inverse Hölder’s inequality on the right-hand side of (13) with indices and it is easy to observe that
Using the following inequality on the term
we get that
Applying inverse Hölder’s inequality on the right-hand side of (17) with indices and it is easy to observe that
Using Fubini’s theorem, we observe that
Using the fact and , we get that
This completes the proof. □
Remark 1.
In Theorem 1, if , , we get the result due to Zhao et al. [8] (Theorem 2).
As a special case of Theorem 1, when , , we have and we get the following result.
Corollary 1.
Let and be n sequences of non-negative numbers defined for and and define
Then,
where
Remark 2.
Let and change to and respectively, and with suitable changes, we have the following new corollary:
Corollary 2.
Let be satisfied. Then, for and we find that
where
Remark 3.
In Corollary 2, if we take , , then the Inequality (21) changes to
where
.
Remark 4.
This is an inverse of the Inequality (4), which was proved by Pachpatte [15].
Corollary 3.
In Corollary 2, if we take the Inequality (21) becomes
where
Theorem 2.
Let , and be satisfied. Then for and , we have that
Proof.
From the hypotheses of Theorem 2, and using inverse Jensen dynamic inequality, we have
Applying inverse Hölder’s inequality on the right-hand side of (24) with indices and , it is easy to observe that
Using the Inequality (15), on the term , we get that
Integrating both sides of (25) over from to we get that
Applying inverse Hölder’s inequality on the right hand side of (17) with indices and it is easy to observe that
Using Fubini’s theorem, we observe that
By using the fact and we get that
This completes the proof. □
Remark 5.
In Theorem 2, if , we get the result due to Zhao et al. [8] (Theorem 3).
As a special case of Theorem 2, when , , we have we get the following result.
Corollary 4.
Let and be n sequences of non-negative numbers defined for and and define
Then,
Remark 6.
Let be defined as above and
changes to and
respectively, and with suitable changes, we have the following new corollary:
Corollary 5.
Let and be satisfied. Then, for and , we find that
Corollary 6.
In Corollary 5, if we take , then the inequality (21) changes to
Remark 7.
In Corollary 6, if we take , then Inequality (28) changes to
This is an inverse of Inequality (5), which was proved by Pachpatte [15].
Corollary 7.
In Corollary 6, let then Therefore, Inequality (28) changes to
Remark 8.
In Corollary 7, if we take then, the Inequality (30) changes to
This is an inverse inequality of the following inequality, which was proved by Pachpatte [8].
Corollary 8.
In Corollary 5, if we take Inequality (27)
Theorem 3.
Let , and be satisfied. Then, for we have that
where
Proof.
From the hypotheses of Theorem 3, we obtain
From (32) and , it is easy to observe that
Using inverse Jensen’s dynamic inequality, we get that
Applying inverse Hölder’s inequality on the right-hand side of (34) with indices and we obtain
Using the following inequality on the term , where and
We obtain that
From (37), we find that
Integrating both sides of (38) over from to we find that
Applying inverse Hölder’s inequality on the right-hand side of (39) with indices and , we obtain
By using Fubini’s theorem, we observe that
Using the fact and we get that
This completes the proof. □
Remark 9.
In Theorem 3, if , , we get the result due to Zhao et al. [9] (Theorem 1.5).
Remark 10.
In Theorem 3, if we take , , we get the result due to Zhao et al. [9] (Theorem 1.6).
Remark 11.
Let and be satisfied and let and be the same as Theorem 3. Similar to proof of Theorem 3, we have
where
This is an inverse form of Inequality (31).
Corollary 9.
Let and be satisfied. Then, we have that
where
Remark 12.
In Corollary 9, if we take , we get an inverse form of inequality due to Handley et al. [16].
Remark 13.
In Corollary 9, if we take , we get an inverse form of inequality due to Handley et al. [16].
Remark 14.
In Inequality (42), taking then , we have
where
Remark 15.
If we take , , Inequality (43) is an inverse of inequality due to Pachpatte [2].
Remark 16.
If we take , , Inequality (43) is an inverse of inequality due to Pachpatte [2].
3. Conclusions
In this article, we presented some investigations of the -nabla Hilbert inequality on time scales. Some dynamic integral and discrete inequalities, known in the literature, are generalized as special cases of our results. We obtained the discrete and the continuous inequalities as special cases of our main results. In future work, I will ask if it is possible to generalize these results using a q-difference operator.
Author Contributions
A.A.E.-D., D.B. and J.A.; formal analysis, A.A.E.-D., D.B. and J.A.; investigation, A.A.E.-D., D.B. and J.A.; writing–original draft preparation, A.A.E.-D., D.B. and J.A.; writing–review and editing, A.A.E.-D., D.B. and J.A. All authors have read and agreed to the published version of the manuscript.
Funding
This research received no external funding.
Conflicts of Interest
The authors declare no conflict of interest.
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