1. Introduction
Over the past decade, a great number of dynamic Hilbert-type inequalities on time scales has been established by many researchers who were motivated by various applications; see the papers [
1,
2,
3,
4].
For example, Pachpatte [
5] proved that if
are two non-negative sequences of real numbers defined for
and
with
and
are two positive sequences of real numbers defined for
and
where
r are natural numbers. Further
and
and
and
are two real-valued non-negative, convex, and submultiplicative functions defined on
then
where
Additionally, in the same paper [
5], Pachpatte proved that if
with
and
are two positive functions defined for
and
and
for
and
where
are positive real numbers; thus
where
Under the same conditions as seen above, with few modifications, Handley et al. [
6] extended (
1) and (
2) as follows:
and
where
and
In [
7], 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
then
and
where
and
where
A time scale
is an arbitrary, non-empty, closed subset of the set of real numbers
. Throughout the article, we assume that
has the topology that it inherits from the standard topology on
. We define the forward jump operator
for any
by
and the backward jump operator
for any
by
In the preceding two definitions, we set (i.e., if is the maximum of , then ) and (i.e., if is the minimum of , then ), where ∅ denotes the empty set.
A point with is said to be right-scattered if , right-dense if , left-scattered if , and left-dense if . Points that are simultaneously right-dense and left-dense are said to be dense points, whereas points that are simultaneously right-scattered and left-scattered are said to be isolated points.
The forward graininess function is defined for any by .
If is a function, then the function is defined by , that is . Similarly, the function is defined by ; that is, .
The sets , and are introduced as follows: if has a left-scattered maximum , then , otherwise . If has a right-scattered minimum , then , otherwise . Finally, we have .
The interval
in
is defined by
We define the open intervals and half-closed intervals similarly.
Assume
is a function and
. Then
is said to be the delta derivative of
at
if for any
there exists a neighborhood
U of
such that, for every
, we have
Moreover, is said to be delta differentiable on if it is delta differentiable at every .
Similarly, we say that
is the nabla derivative of
at
if, for any
, there is a neighborhood
V of
, such that for all
Furthermore, is said to be nabla differentiable on if it is nabla differentiable at each .
A function is said to be right-dense continuous (rd-continuous) if is continuous at all right-dense points in and its left-sided limits exist at all left-dense points in .
In a similar manner, a function is said to be left-dense continuous (ld-continuous) if is continuous at all left-dense points in and its right-sided limits exist at all right-dense points in .
The delta integration by parts on time scales is given by the following formula
whereas the nabla integration by parts on time scales is given by
The following relations will be used.
- (i)
- (ii)
If
, then
where
and ∇ are the forward and backward difference operators, respectively.
Now we will introduce the diamond-
calculus on time scales, and we refer the interested reader to [
8,
9] for further details on the definitions of nabla and delta integrals and derivatives.
If
is a time scale, and
is a function that is delta and nabla differentiable on
,then, for any
, the diamond-
dynamic derivative of
at
, denoted by
, is defined by
We conclude from the last relation that a function is diamond- differentiable if and only if it is both delta and nabla differentiable. For , the diamond- derivative boils down to a delta derivative, and for it boils down to a nabla derivative.
Assume , are diamond- differentiable functions at , and let . Then
- (i)
;
- (ii)
;
- (iii)
.
Let
be a continuous function. Then the definite diamond-
integral of
is defined by
Let a, b, , . Then,
- (i)
;
- (ii)
;
- (iii)
;
- (iv)
;
- (v)
;
- (vi)
if on , then ;
- (vii)
if on , then ;
- (viii)
.
Let be a differentiable function on . Then is increasing if , non-decreasing if , decreasing if , and non-increasing if on .
Next, we write Hölder’s inequality and Jensen’s inequality on time scales.
Lemma 1 (Dynamic Hölder’s Inequality [
3]).
Suppose with Assume be integrable functions and with thenThis inequality is reversed if and if or
Lemma 2 (Dynamic Jensen’s inequality [
3]).
Let , and If and is convex thenThis inequality is reversed if is concave.
Definition 1. Φ is called a supermultiplicative function on if In this paper, we extend some generalizations of the integral Hardy–Hilbert inequality to a general time scale using diamond alpha calculus. As special cases of our results, we will recover some dynamic integral and discrete inequalities known in the literature.
Now we are ready to state and prove our main results.
2. Main Results
First, we enlist the following assumptions for the proof of our main results:
- (S1)
be time scales with
- (S2)
are non-negative, diamond-Alpha integrable functions defined on
- (S3)
have partial -derivatives and with respect and , respectively.
- (S4)
All functions used in this section are integrable according to sense.
- (S5)
- (S6)
are n positive diamond-Alpha integrable functions defined for
- (S7)
and are positive diamond-Alpha integrable functions defined for
- (S8)
are n real-valued non-negative concave and supermultiplicative functions defined on
- (S9)
and are positive real numbers.
- (S10)
and
- (S11)
- (S12)
- (S13)
- (S14)
- (S15)
- (S16)
- (S17)
and
- (S18)
- (S19)
- (S20)
- (S21)
- (S22)
- (S23)
is positive real number.
- (S24)
- (S25)
- (S26)
are n positive functions.
- (S27)
- (S28)
- (S29)
Now, we are ready to state and prove the main results that extend several results in the literature.
Theorem 1. Let , , and be satisfied. Then for and we find thatwhere Proof. From the hypotheses of Theorem 1,
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 (
21) with indices
and
it is easy to observe that
By using the following inequality on the term
we get that
Integrating both sides of (
24) over
from
to
we obtain that
Applying inverse Hölder’s inequality on the right hand side of (
25) 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 1. In Theorem 1, if , we get the result due to Zhao et al. ([10], Theorem 2). As a special case of Theorem 1, when , we have we get the following result.
Corollary 1. Let and be n sequences of non-negative numbers defined for and and define Remark 2. Let and change to and respectively; with suitable changes, we have the following new corollary:
Corollary 2. Let and be satisfied. Then for and we have thatwhere Corollary 3. In Corollary 2, if we take then the inequality (28) changes towhere Remark 3. In Corollary 3, if we take then the inequality (29) changes towhere This is an inverse of the inequality (6) which was proved by Pachpatte [7]. Corollary 4. In Corollary 2, if we take the inequality (28) becomeswhere Theorem 2. Let , and be satisfied. Then for and we have that Proof. From the hypotheses of Theorem 2, and by using inverse Jensen dynamic inequality, we have
Applying inverse Hölder’s inequality on the right hand side of (
32) with indices
and
it is easy to observe that
By using the inequality (
23), on the term
we get that
Integrating both sides of (
33) over
from
to
we get that
Applying inverse Hölder’s inequality on the right hand side of (
25) with indices
and
it is easy to observe that
By using Fubini’s theorem, we observe that
By using the fact
and
we get that
This completes the proof. □
Remark 4. In Theorem 2, if , we get the result due to Zhao et al. ([10], Theorem 3). As a special case of Theorem 2, when , we have we get the following result.
Corollary 5. Let and be n sequences of non-negative numbers defined for and and define Remark 5. Let andchanges to andrespectively, and with suitable changes, we have the following new corollary: Corollary 6. Let and be satisfied. Then, for and , we have that Corollary 7. In Corollary 6, if we take then the inequality (28) changes to Remark 6. In Corollary 7, if we take then the inequality (37) changes to This is an inverse of the inequality (7), which was proven by Pachpatte [7]. Corollary 8. In Corollary 7, let then Therefore, inequality (37) changes to Remark 7. In Corollary 8, if we take then inequality (39) changes to This is an inverse inequality of the following inequality which was proven by Pachpatte [10]. Corollary 9. In Corollary 6, if we take the inequality (30) Theorem 3. Let , and be satisfied. Then, for we have thatwhere Proof. From the hypotheses of Theorem 3, we obtain
From (
41) and
, it is easy to observe that
By using inverse Jensen’s dynamic inequality, we get that
Applying inverse Hölder’s inequality on the right hand side of (
43) with indices
and
we obtain
Using the following inequality on the term
where
and
Integrating both sides of (
47) over
from
to
we get that
Applying inverse Hölder’s inequality on the right hand side of (
48) with indices
and
we obtain
By using Fubini’s theorem, we observe that
By using the fact
and
we get that
This completes the proof. □
Remark 8. In Theorem 3, if , we get the result due to Zhao et al. ([11], Theorem 1.5). Remark 9. In Theorem 3, if we take , we get the result due to Zhao et al. ([11], Theorem 1.6). Remark 10. Let and be satisfied and let and be as Theorem 3. Similar to proof of Theorem 3, we havewhere This is an inverse form of the inequality (40). Corollary 10. Let and be satisfied. Then we have thatwhere Remark 11. In Corollary 10, if we take we get an inverse form of inequality (3), which was given by Handley et al. Remark 12. In Corollary 10, if we take we get an inverse form of inequality (4), which was given by Handley et al. Remark 13. In inequality (51) taking then , we havewhere Remark 14. If we take , the inequality (52) is an inverse of inequality of (1), which was given by Pachpatte. Remark 15. If we take , the inequality (52) is an inverse of inequality of (2), which was given by Pachpatte.