Abstract
Several inverse integral inequalities were proved in 2004 by Yong. It is our aim in this paper to extend these inequalities to time scales. Furthermore, we also apply our inequalities to discrete and continuous calculus to obtain some new inequalities as special cases. Our results are proved using some algebraic inequalities, inverse Hölder’s inequality and inverse Jensen’s inequality on time scales. Symmetry plays an essential role in determining the correct methods to solve dynamic inequalities.
MSC:
26D10; 26D15; 26E70; 34A40
1. Introduction
The form of the established classical discrete Hardy–Hilbert double series inequality [1] is given as follows: If , , and then we have
where , .
The continuous versions of inequality (1) is given by:
unless or where f and g are measurable non-negative functions such that and . The constant in (1) and (2), is the best possible.
In [2], Pachpatte proved that if with and q are two positive functions defined for and with and for and , where y are positive real numbers. Let and be two real-valued non-negative, convex and sub-multiplicative functions defined on Then,
where
In 2004, Yong [3] studied the following integral inequality:
Theorem 1.
Let and for , where ζ are positive real numbers and define
for and Then, for or
unless or where
In 2009, Yang [4] studied the following integral inequality:
Theorem 2.
Let and for , where ζ are positive real numbers and define
for and Then,
unless or where
In this paper, we prove some new dynamic inequalities of Hilbert type and their converses on time scales. From these inequalities, as special cases, we formulate some special integral and discrete inequalities. Symmetry plays an essential role in determining the correct methods to solve dynamic inequalities.
Now, we present some fundamental concepts and effects on time scales which are beneficial for deducing our main results. In 1988, S. Hilger [5] presented time scale theory to unify continuous and discrete analysis. For some Hilbert-type integral, dynamic inequalities and other types of inequalities on time scales, see the papers [2,3,6,7,8,9,10,11,12,13,14,15,16]. For more details on time scale calculus see [17].
We need the following important relations between calculus on time scales and either continuous calculus on or discrete calculus on . Note that:
- (i)
- If , then
- ()
- If , then
Next, we write Hölder’s inequality and Jensen’s inequality on time scales.
Lemma 1
(Dynamic Hölder’s Inequality [18]). Let and f, . If p, with , then
This inequality is reversed if and if or
Lemma 2
(Dynamic Jensen’s Inequality [18]). Let a, and c, . Assume that and are non-negative with . If is a convex function, then
This inequality is reversed if is concave.
Moreover, we use the following definition and lemma as we see in the proof of our results:
Definition 1.
Λ is called a supermultiplicative function on if
Lemma 3
([19]). Let be a time scale with such that If and then
Now, we present the formula that reduces double integrals to single integrals, which is desired in [9].
Lemma 4.
Let and Then,
assuming the integrals considered exist.
The following section contains our main results:
2. Main Results
In the next theorems, we assume that and
Theorem 3.
Let be time scale with and ζ Assume and are two non-negative and right-dense continuous functions on and , respectively, and define
then, for and we have that
where
Proof.
By using the inequality (11), we obtain
Applying inverse Hölder’s inequality on the right hand side of (14) with indices p and we have
Applying inverse Hölder’s inequality on the right hand side of (15) with indices and we also have that
From (16) and (17), we obtain
Using the following inequality
where and Now, by setting and we obtain that
Substituting (20) in (18), yields
Dividing both side of (21) by , we obtain that
Integrating both sides of (22) from to and from to , and applying inverse Hölder’s inequality with indices and we obtain
Applying Lemma 4 on the right hand side of (23), we have
By using the facts and we obtain
This completes the proof. □
Theorem 4.
Let and be defined as Theorem 3. Then, we have
Proof.
Put in (13). This completes the proof. □
As a special case of Theorem 3, when , we have , and we obtain the following result:
Corollary 1.
Assume that and are non-negative functions and define and Then,
where
As special case of Theorem 3, when , we have , and we obtain the following result:
Corollary 2.
Assume that and are non-negative sequences and define
Then,
where
Theorem 5.
Let be a time scale with and be as defined in Theorem 3. Let and be two non-negative and right-dense continuous functions on and , respectively. Suppose that Λ and Υ are non-negative, concave and supermultiplicative functions defined on . Furthermore, assume that
then, for and we have that
where
Proof.
Since is a concave and supermultiplicative function, we obtain by applying inverse Jensen’s inequality that
Applying inverse Hölder’s inequality with indices p and on the right hand side of (26), we see that
Moreover, since is a concave and supermultiplicative function, we obtain by applying inverse Jensen’s inequality and inverse Hölder’s inequality with indices and that we have
From (27) and (28), we have
By using inequality (19), we obtain that
From (29) and (30), we have that
Then,
Integrating both sides of (32) from to and from and , we obtain
Applying inverse Hölder’s inequality with indices and on the right hand of side (33), we have
Applying Lemma 4 on the right hand side of (34), we obtain
By using the facts and we obtain
where
This completes the proof. □
As a special case of Theorem 5, when , we have , and we obtain the following result:
Corollary 3.
Assume that and are non-negative functions and define
Then,
where
As a special case of Theorem 5, when , we have , and we obtain the following result.
Corollary 4.
Assume that and are non-negative sequences and define
Then,
where
Theorem 6.
Let be a time scale with Let f and g be two non-negative and right-dense continuous functions on and , respectively. Suppose that Λ and Υ are non-negative, concave and supermultiplicative functions defined on and define
then, for and we have that
where
Proof.
By assumption and by using the inverse Jensen inequality, we see that
By applying inverse Hölder’s inequality on (37) with indices, we have
This implies that
Analogously,
From (39) and (40), we obtain
By using inequality (19), we obtain that
Then,
From (43), we have
Taking delta integrating on both sides of (44), first over ℑ from to and then over from to we find that
By applying inverse Hölder’sinequality on (45) with indices and we get
Applying Lemma 4 on (46), we fined that
By using the facts and we obtain
where
This completes the proof. □
As a special case of Theorem 6, when we obtain the following conclusion.
Corollary 5.
Assume that f and g are non-negative functions and define
then, for and we have that
where
As a special case of Theorem 6, when we obtain the following conclusion.
Corollary 6.
Assume that and are two non-negative sequences of real numbers and define
then,
where
Theorem 7.
Let be a time scale with Let and be two non-negative and right-dense continuous functions on and , respectively. Let Λ and Υ be as assumed in Theorem 5. Furthermore, assume that
then, for and we have that
where
Proof.
From (47), we see that
Applying inverse Hölder’s inequality with indices p and on the right hand side of (48), we obtain
From (49), we obtain that
Similarly, we obtain
From (50) and (51), we observe that
Applying the inequality (19) on the term we obtain the following inequality
Dividing both sides of (53) by we obtain that
Integrating both sides of (54) from to and to we obtain
Applying inverse Hölder’s inequality again with indices and on the right hand side of (55), we have
Applying Lemma 4 on the right hand side of (56), we obtain that
By using the facts and we obtain
This completes the proof. □
As a special case of Theorem 7, when , we have , and we obtain the following result:
Corollary 7.
Assume that and are non-negative functions and define
Then,
where
As a special case of Theorem 7, when , we have , and we obtain the following result:
Corollary 8.
Assume that and are non-negative sequences and define
Then
where
3. Conclusions and Discussion
In this article, with the help of the inverse Hölder’s inequality and inverse Jensen’s inequality on time scales, we discussed and proved several new generalizations of the integral retarded inequalities given in [3]. Moreover, we generalized a number of other inequalities to a general time scale. Finally, as a special case, we studied the discrete and continuous inequalities. As a future work, we intend to generalize these inequalities by using alpha-conformable fractional derivatives on time scales. Furthermore, we will extend these results to diamond alpha calculus.
Author Contributions
Conceptualization, A.A.E.-D., S.D.M. and B.A.; formal analysis, A.A.E.-D., S.D.M. and B.A.; investigation, A.A.E.-D., S.D.M. and B.A.; writing–original draft preparation, A.A.E.-D., S.D.M. and B.A.; writing–review and editing, A.A.E.-D., S.D.M. and B.A. All authors have read and agreed to the published version of the manuscript.
Funding
Princess Nourah bint Abdulrahman University Researchers Supporting Project number PNURSP2022R216, Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia.
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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