Abstract
In this important work, we discuss some novel Hilbert-type dynamic inequalities on time scales. The inequalities investigated here generalize several known dynamic inequalities on time scales and unify and extend some continuous inequalities and their corresponding discrete analogues. Our results will be proved by using some algebraic inequalities, Hölder inequality, and Jensen’s inequality on time scales.
1. Introduction
The celebrated Hardy-Hilbert’s integral inequality [1] is
where , . Putting , we get:
where the constants and are the best possible.
Over the past decade, a great number of dynamic Hilbert-type inequalities on time scales have been established by many researchers who were motivated by some applications; see the papers [2,3,4,5,6,7,8,9,10,11,12,13]. For more details on time scales calculus, see [14].
In this paper, we extend some generalizations of the integral Hardy-Hilbert inequality to a general time scale. As special cases of our results, we will recover some dynamic integral and discrete inequalities known in the literature.
A time scale is an arbitrary non-empty closed subset of the real number. We define forward and backward jump operators and respectively by
We will need the following important relations between calculus on time scales and either continuous calculus on or discrete calculus on . Note that:
- (i)
- If , then
- (ii)
- If , then
Next, we write Hölder’s inequality and Jensen’s inequality on time scales.
Lemma 1
([3]). Let with Assume , be integrable functions and with . Then
This inequality is reversed if and if or
Lemma 2
([15]). Let , and If , and is convex, then
This inequality is reversed if is concave.
Theorem 1
(Chain rule on time scales [14]). Assume is continuous, is -differentiable on , and is continuously differentiable. Then there exists with
Definition 1.
Φ is called a supermultiplicative function on if
Next, we write Fubini’s theorem on time scales.
Lemma 3
(Fubini’s Thoerem, see [16]). Assume that and are two finite-dimensional time scales measure spaces. Moreover, suppose that is a delta integrable function and define the functions
and
Then ϕ is delta integrable on ς, and ψ is delta integrable on ϑ and
Now we are ready to state and prove our main results.
2. Main Results
First, we enlist the following assumptions for the proofs of our main results:
- be time scales with
- are nonnegative, delta integrable functions defined on
- have a partial - derivatives and with respect and respectively.
- All functions used in this section are integrable according to sense.
- are n positive delta integrable functions defined for
- and are positive delta integrable functions defined for
- are n real-valued nonnegative concave and supermultiplicative functions defined on
- and are positive real numbers.
- and
- and
- is positive real number.
- are n positive functions.
Now, we are ready to state and prove the main results that extend several results in the literature.
Theorem 2.
Let and be satisfied. Then for we have
where
Proof.
From the hypotheses of Theorem 2, we obtain
From (10) and , it is easy to observe that
By using inverse Jensen’s dynamic inequality, we get
Applying inverse Hölder’s inequality on the right hand side of (12) with indices and we obtain
Using the following inequality on the term , where and
we obtain that
From (15), we obtain that
Integrating both sides of (16) over from to we get
Applying inverse Hölder’s inequality on the right hand side of (17) with indices and we obtain
By using Fubini’s theorem, we observe that
By using the facts and we get
This completes the proof. □
Remark 1.
In Theorem 2, if , we get the result due to Zhao et al. ([17], Theorem 1.5).
Remark 2.
In Theorem 2, if we take , we get inequality due to Zhao et al. [17].
Remark 3.
Let and be satisfied and let γ, and be as in Theorem 2. Similar to proof of Theorem 2, we have
where
This is an inverse form of the inequality (9).
Corollary 1.
Let , and be satisfied. Then we have
where
Remark 4.
In Corollary 1, if we take we get an inverse form of inequality due to Handley [18].
Remark 5.
In Corollary 1, if we take we get an inverse form of inequality due to Handley [18].
Remark 6.
Remark 7.
If we take , the inequality (21) is an inverse of inequality due to Pachpatte [19].
Remark 8.
If we take , the inequality (21) is an inverse of inequality due to Pachpatte [19].
Theorem 3.
Let and be satisfied. Then for and , we have
where
Proof.
From the hypotheses of Theorem 3, and it is easy to observe that
By using inverse Jensen dynamic inequality, we obtain that
Applying inverse Hölder’s inequality on the right hand side of (24) with indices and it is easy to observe that
By using inequality the following inequality on the term we get
Integrating both sides of (27) over from to we obtain that
Applying inverse Hölder’s inequality on the right hand side of (28) with indices and it is easy to observe that
Using Fubini’s theorem, we observe that
By using the facts and we get
This completes the proof. □
Remark 9.
In Theorem 3, if , we get the result due to Zhao et al. [20] (Theorem 2).
As a special case of Theorem 3, when , we have and we get the following result.
Corollary 2.
Let and be n sequences of non-negative numbers defined for and and define
Then
where
Remark 10.
Let and change to , and respectively, and with suitable changes, and we have the following result:
Corollary 3.
Let and be satisfied. Then for and we have that
where
Corollary 4.
In Corollary 3, if we take , then the inequality (31) changes to
where
Remark 11.
In Corollary 4, if we take then the inequality (32) changes to
where
This is an inverse of the inequality due to Pachpatte [21].
Corollary 5.
In Corollary 3, if we take , the inequality (31) becomes
where
Theorem 4.
Let and be satisfied. Then for , and , we have
Proof.
From the hypotheses of Theorem 4, and by using inverse Jensen dynamic inequality, we have
Applying inverse Hölder’s inequality on the right hand side of (35) with indices and it is easy to observe that
By using the inequality (26) on the term , we get
Integrating both sides of (36) over from to we get
Applying inverse Hölder’s inequality on the right hand side of (37) with indices and it is easy to observe that
By using Fubini’s theorem, we observe that
By using the facts and we get
This completes the proof. □
Remark 12.
In Theorem 4, if , we get the result due to Zhao et al. [20] (Theorem 3).
As a special case of Theorem 4, when , we have and we get the following result.
Corollary 6.
Let and be n sequences of non-negative numbers defined for and and define
Then
Remark 13.
Let and
changes to and
respectively, and with suitable changes, we have the following result:
Corollary 7.
Let , and be satisfied. Then for , and , we have
Corollary 8.
In Corollary 7, if we take , then the inequality (39) changes to
Remark 14.
In Corollary 8, if we take then the inequality (40) changes to
This is an inverse of the inequality due to Pachpatte [21].
Corollary 9.
In Corollary 8, let then Therefore, the inequality (40) changes to
Remark 15.
In Corollary 9, if we take then the inequality (42) changes to
This is an inverse inequality of the following inequality, which was proved by Pachpatte [20].
Corollary 10.
In Corollary 7, if we take , the inequality (39)
3. Conclusions
In this article, we gave some generalizations of the Hardy-Hilbert inequality on a general time scale, and some dynamic integral and discrete inequalities known in the literature were extended as special cases of our results.
Author Contributions
Conceptualization, H.M.E.-O., A.A.E.-D., S.D.M., D.B. and C.C.; formal analysis, H.M.E.-O., A.A.E.-D., S.D.M., D.B. and C.C.; investigation, H.M.E.-O., A.A.E.-D., S.D.M., D.B. and C.C.; writing—original draft preparation, H.M.E.-O., A.A.E.-D., S.D.M., D.B. and C.C.; writing—review and editing, H.M.E.-O., A.A.E.-D., S.D.M., D.B. and C.C. All authors have read and agreed to the published version of the manuscript.
Funding
This research received no external funding.
Institutional Review Board Statement
Not applicable.
Informed Consent Statement
Not applicable.
Data Availability Statement
Not applicable.
Conflicts of Interest
The authors declare no conflict of interest.
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