Abstract
Some weighted classes of hyperbolic function spaces are defined and studied in this paper. Finally, by using the chordal metric concept, some investigations for a class of general hyperbolic functions are also given.
1. Introduction
In the theory of holomorphic function spaces, the Besov and Bloch classes remain vital instruments which ensure the settings of Banach spaces. However, a good number of researchers generalized and extended these types of function spaces in certain numerous ways by choosing relevant weights, and by using auxiliary types of functions (hyperbolic, meromorphic, quaternion) as well as enlarging the classes of weighted function spaces for this kind of studied.
The major purpose of the present manuscript is to provide certain specific general concepts by concerned hyperbolic functions and discussing their properties in which the essentiality of the obtained results. What follows is a brief introduction to the concerned hyperbolic-type of function spaces.
To act the concerned aim, the symbol defines the open unit disk. In addition, the symbol stands for the space of all holomorphic functions in . Assuming also that is a concerned subset of consisting of those for which for all . Furthermore, let be the concerned normalized area measure on .
Moreover, the concerned Green’s function of is given by with , where the points may define a concerned Möbius transformation by the concerned singular point
Suppose that defines a concerned metric space, then the concerned open and the concerned closed balls with center u and radius can be defined by respectively.
Let define the concerned hyperbolic derivative of A specific function is said to belong to the hyperbolic -Bloch class if
The little concerned hyperbolic Bloch-type class consists of all for which
The symbol ≃ is used to express specific comparability.
We will use to inform that there exists a positive constant k such that . The symbol ≳ can be also explained in a same way. During this manuscript, and are used to denote specific positive constants.
Let The symbol stands for pseudo-hyperbolic disk, with
Now, we introduce the following concerned general hyperbolic derivative:
Remarking that, when , then the usual hyperbolic derivative is obtained.
Throughout this manuscript both of the function which maps from the interval into the interval the condition holds. Furthermore, the concerned weight function E which maps from the interval into itself is a right-continuous and nondecreasing concerned functions.
We are interested in the class of all hyperbolic functions which we define it by:
In addition, we define the class of general weighted hyperbolic functions by:
Another interesting class of hyperbolic functions can be introduced as follows:
Definition 1.
The concerned function is belonging to the hyperbolic classes if
Remark 1.
When and and considering the case of analytic or meromorphic functions, then we obtain some weighted analytic or meromorphic classes from the concerned classes which are researched by a number of authors (see [1,2,3,4,5] and others). On the other hand there are some results in Clifford analysis (see [6,7,8,9,10] and others).
Remark 2.
It is said that the hyperbolic space is trivial when consisting of constant functions only. Furthermore, the hyperbolic space can be also trivial or not, this may be determined after considering the behavior of the concerned integral (convergent or divergent)
Proposition 1.
- (i)
- When the concerned integral then the hyperbolic space must be trivial.
- (ii)
- When the concerned integral so
2. Hyperbolic Type Classes
We investigate some general hyperbolic classes and their connection with some others. Important concerned properties of the used weights are also discussed. It is demand to see for what specific functions belonging to the concerned hyperbolic classes in may be null (trivial).
Theorem 1.
If the integral (3) diverges, thus the concerned hyperbolic spaces will contain specific constant functions only.
Proof.
The proof can be obtained from the following concerned calculations,
which implies a contradiction, therefore the proof is established. □
As proved in [11], we will state the next result.
Theorem 2.
Assuming that and let
Thus,
where is a constant.
Remark 3.
Theorem 1 is introduced for hyperbolic functions but Yamashita’s result in [11] is proved for meromorphic functions. When we put and replacing the by then Yamashita’s result [11] can be obtained.
The following interesting question is considered.
Question 1
Let and assume that is the condition
can be an actual necessary and sufficient to hold that ?
Concerned Answer
When (4) satisfies, so Hence, On the other hand suppose that Further because E is bounded, it is very clear to find that the condition (4) can be satisfied. If E is unbounded and hence the specific supremum in (4) must be infinite ∀ To verify the assumption, we remark by Theorem 1 that when we deduce that
When then
Hence,
Letting we cannot obtain condition (4) with therefore the concerned proof is finished.
Therefore, the concerned above condition (4) can be given as an actual sufficient condition for which the function can be used to be an actual necessary condition when the concerned weight function E is bounded too.
For the other case when we consider unbounded function suppose that it is not hard to show that (4) can be satisfied clearly.
The weighted functions playing essential roles in studying Some questions on the weights can be stated as follows:
Question 2
What further restrictions on the weighted functions E and may be added for ?
When the concerned hyperbolic classes as well as can be congruent if ?
In what follows we give answers for these important questions.
Proposition 2.
Suppose that when Thus,
Now, the following elemental result shall be proved.
Theorem 3.
Suppose that thus we have
for some certain constant
Proof.
Suppose that Then for we have that
Thus, (6) holds by choosing r small enough.
On the other hand, assume that be the supremum in (6) which is given for some certain Assuming that . Because we obtain that
Thus, regarding to Theorem 1, then the concerned proof is completely finished. □
Corollary 1.
Letting When as well as
then
To act an interesting property on weights of hyperbolic-type spaces, the next emerging result shall be presented.
Theorem 4.
Suppose that also let
- (i)
- When the boundedness of the functions are hold, hence
- (ii)
- When the boundedness of the functions are not hold, so
Proof.
- (i)
- Suppose that the weights are bounded, thenHence, it is obvious to see that
- (ii)
- By using Proposition 2, the following inclusion can be obtained
Suppose that Noting that in . (For this pseudo-hyperbolic disk, we have ). By comparing the concerned integrals that defining the classes as well as , it is enough to consider some certain integrals on . In view of the concerned hypotheses we infer that
Hence therefore the concerned result is established completely. □
Some restrictions on the weighted function as well as on the function which make guarantee that
will be described in the next interesting result.
Theorem 5.
Let as well as be two weighted functions which both satisfying boundedness condition or both are not have boundedness condition. In addition assume that when . Thus
Proof.
Defining the weighted functions , When the functions and are both bounded, then using the concerned hypothesis, we infer that
where c and are two positive specific constants. Further, it is not hard to deduce that
When, we have the unbounded case for the weighted functions and using Theorem 4, we thus obtain that
Then, the proof is completely obtained. □
Theorem 6.
- (i)
- If are unbounded and (3) holds, then the equality holds.
- (ii)
- If are bounded and (3) holds, then the equality holds too.
- (iii)
- In the assertion (i) (respectively (ii)), the concerned condition (3) is an actual necessary condition for the equality (respectively also the equality ).
Proof.
For the proof of (i), the inclusion can be obtained from the use of Proposition 2. On the other hand, when we have that
hence
(ii) Since, we have that
Hence, we can prove that
If then we may find which
Now, we prove that we may get a concerned constant for which
Hence, we estimate
Let where and In view of with
we consider now the constant such concerned disks, where M is a concerned an absolute positive constant. Then,
Setting Then, we have
From (3). We have deduced that (7) can be satisfied,
Since, we can infer that
Hence, using (7) and (8) with replaced by that
this proves (ii) in Theorem 6.
(iii) For functions and in for which
If we have
Hence the concerned condition (3) is verified. Therefore, (iii) is completely established, hence the concerned proof of Theorem 6 is obtained completely. □
On the boundary of the unit disc, we have following emerging spaces:
Furthermore, the weighted hyperbolic Dirichlet class that can be given by
Theorem 7.
Theorem 8.
Suppose that the condition (3) is satisfying, thus the equality
can be obtained.
Remark 4.
It is enough and not hard to show that the inclusion
can be verified.
Theorem 9.
- (a)
- Suppose that , hence
- (b)
- For the weighted hyperbolic Dirichlet-type space, we obtain that
- (c)
- Suppose that Let thus
- (d)
- When the equalityholds, the following concerned equality can be deduced.
Proof.
To prove (a), we will suppose first that by noting the inclusion
also assuming the boundedness for the functions E and it is obvious to see that
The second case is to suppose that are not bounded functions, then by Theorem 3 and since
we infer that
then (a) is proved. Furthermore, the proof of (b) is not hard.
To act the proof of (c), we note from (b) and the concerned hypothesis that
If the hypothesis in (d) holds, we can obtain that and the inclusion is obtained using (b). □
Corollary 2.
where,
Corollary 3.
where,
3. Chordal Metric
The chordal metric between the two concerned points z and w in the known extended complex plane is given by (see [12]):
For, the concerned hyperbolic Bergman class can be given as the set of those for which
In view of the concerned chordal metric, the following concerned result shall be proved.
Theorem 10.
Assuming and let Suppose that
Then, we can find a constant for which
Proof.
Now, assume and Hence,
Therefore, from integration method by parts and applying Fubini’s theorem, we deduce
this is the needed concerned asymptotic inequality when For the case of we can find
Applying the inequality of Hlder, we deduce
therefore Fubini’s theorem implies that
This completes the proof. □
Remark 5.
Studying some certain differential equations evolving some specific analytic function spaces were discussed by some authors (see [13,14]). For the defined general hyperbolic classes, the next question can be stated as follows:
How one can apply some classes of hyperbolic-type to solve some specific differential equations?
4. Conclusions
The theory of complex function spaces has received interesting extensive attention due to its numerous applications in many branches of mathematics such as complex analysis, operator theory, measure theory, differential equations as well as functional analysis. The study of this theory depends on many tools.
The study of hyperbolic functions has been researched by many authors (see [15,16,17,18,19] and others).
Special attention of some generalizations of certain classes of weighted hyperbolic function spaces by using a general hyperbolic derivative is the object of this paper.
To this end, we propose interesting characterizations, a novel of general hyperbolic differentially private evolving hyperbolic-type of function classes releasing the general derivative which reduces the scales and tool up a clear utility. Moreover, a chordal metric characterization is presented for a class of hyperbolic functions.
Funding
This research received no external funding.
Institutional Review Board Statement
Not applicable.
Informed Consent Statement
Not applicable.
Data Availability Statement
For the data it is not applicable to this concerned paper as no concerned data-sets were created or used through this concerned study.
Acknowledgments
The author would like to thank Taif University Researchers supporting Project number (TURSP-2020/159), Taif University-Saudi Arabia. The author would like to thank the anonymous concerned reviewers for their valuable remarks on this study.
Conflicts of Interest
The author declares that he has no competing interest.
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