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Awad A. Bakery, M. H. El Dewaik, "Kannan Contraction Operator on the Domain of -Cesàro Matrix in and Related Prequasi Ideal with an Application of Nonlinear Difference Equations", Journal of Function Spaces, vol. 2021, Article ID 9928947, 18 pages, 2021. https://doi.org/10.1155/2021/9928947
Kannan Contraction Operator on the Domain of -Cesàro Matrix in and Related Prequasi Ideal with an Application of Nonlinear Difference Equations
In this article, the sequence space has been built by the domain of -Cesàro matrix in Nakano sequence space , where and are sequences of positive reals with , and , with . Some topological and geometric behavior of , the multiplication maps acting on , and the eigenvalues distribution of operator ideal constructed by and -numbers have been examined. The existence of a fixed point of Kannan prequasi norm contraction mapping on this sequence space and on its prequasi operator ideal are investigated. Moreover, we indicate our results by some explanative examples and actions to the existence of solutions of nonlinear difference equations.
As a remark of constant Lebesgue spaces, variable exponent Lebesgue spaces go again many years, and in successive centuries, variable Lebesgue and Sobolev spaces have been regularly studied. Next, many variable exponent real function spaces and complex function spaces have presented, for instance, Morrey spaces, Herz-Morrey spaces, Herz spaces, Hardy spaces, Besov spaces, Trieble-Lizorkin spaces, Fock spaces, Bessel potential spaces, and Bergman spaces with variable exponents. For three centuries, variable exponent function spaces have been extensively applied in approximation theory, image processing, and differential equations, and many variable exponent real function spaces and complex function spaces have shown. Thus far, the theory of variable exponent function spaces has pensively built upon on the boundedness of the Hardy-Littlewood maximal operator. This confines its technique in differential equations, optimization, and approximation. The spaces of all, bounded, -absolutely summable and convergent to zero sequences of complex numbers will be denoted by , , , and . . We denote the space of all, finite rank, approximable, and compact bounded linear maps from a Banach space into a Banach space by , , , and , and if , we indicate , , , and , respectively. The ideal of all, finite rank, approximable, and compact maps are indicated by , , , and . We label as 1 lies at the th coordinate, with
Definition 1 . A function is called an -number, if the sequence for any , satisfies the following setup: (a), with (b) with and , (c), for all , , and , where and are any two Banach spaces(d)If and , then (e)Suppose , then , for all (f) or , where indicates the unit operator on the -dimensional Hilbert space We give some examples of -numbers as follows: (1)The -th Kolmogorov number, , where(2)The -th approximation number, , where
Notations 2 .
Some of ideals in the class of Banach spaces or Hilbert spaces are generated by scalar sequence spaces. For example, the ideal of compact maps is constructed by the space and , for . Pietsch  investigated the quasi-ideals for . He examined that the ideals of nuclear maps and of Hilbert Schmidt maps between Hilbert spaces are formed by and , respectively. He discussed that are dense in , and the algebra , where , generated simple Banach space. Pietsch  established that with , is small. Makarov and Faried  proved that for every infinite dimensional Banach spaces , , and , hence . Yaying et al.  constructed the sequence space, , whose its -Cesàro matrix in , with and . They studied the quasi Banach ideal of type , with and . They introduced its Schauder basis, , , and duals and determined certain matrix classes related to this sequence space. On sequence spaces, Baarir and Kara examined the compact maps on some Euler -difference sequence spaces , some difference sequence spaces of weighted means , the Riesz -difference sequence space , the -difference sequence space derived by weighted mean , and the th order difference sequence space of generalized weighted mean . Mursaleen and Noman [12, 13] established the compact operators on some difference sequence spaces. Alotaibi et al. [14, 15] examined the compact operators on some Fibonacci difference sequence spaces and on a new sequence space related to spaces. The multiplication maps on Cesàro sequence spaces equipped with the Luxemburg norm investigated by Komal et al. . lkhan et al. , investigated the multiplication maps on Cesàro second order function spaces. Recently, many authors in the literature have investigated some nonabsolute type sequence spaces and brought current exquisite papers, for examples, Mursaleen and Noman  introduced the sequence space and of nonabsolute type and proved that the spaces and are linearly isomorphic for , is a -normed space and a -space in the cases for and and constructed the basis of the space for . In , they examined the , , and duals of and of nonabsolute type, with . They detailed some related matrix classes and developed the properties of some other classes by means of a given basic lemma. On Cesàro summable sequences, Mursaleen and Baar  introduced some spaces of double sequences whose Cesàro transforms are bounded, convergent in the Pringsheim’s sense, null in the Pringsheim’s sense, both convergent in the Pringsheim’s sense and bounded, regularly convergent, and absolutely -summable, respectively, and investigated some topological properties of those sequence spaces. The Banach fixed point theorem  gave many mathematicians the way to examine many generalizations for the contraction maps defined on the space or on the space itself. Kannan  investigated an example of a class of operators with the identical fixed point actions as contractions though that fails to be continuous. Ghoncheh  was the only one who examined Kannan operators in modular vector spaces. He showed that the existence of a fixed point of Kannan mapping in complete modular spaces that have Fatou property. Bakery and Mohamed  explored the concept of the prequasi norm on Nakano sequence space such that its variable exponent in . They explained the sufficient conditions on its equipped with the definite prequasi norm to generate prequasi Banach and closed space and examined the Fatou property of different prequasi norms on it. More, they showed the existence of a fixed point of Kannan prequasi norm contraction maps on it and on the prequasi Banach operator ideal constructed by -numbers which belong to this sequence space. The next inequality will used in the sequel : Assume and , for all , and , then
The aim of this paper is arranged as follows: In Section 3, we introduce the definition and some inclusion relations of the sequence space under the function . In Section 4, we investigate the enough setup on with definite function to form premodular private sequence space (), which gives that is a prequasi normed . In Section 5, we examine a multiplication map on and introduce the necessity and sufficient conditions on this sequence space such that the multiplication map is bounded, approximable, invertible, Fredholm, and closed range. In Section 6, firstly, we introduce the sufficient settings (not necessary) on, such thatis dense in. This investigates a negative answer of Rhoades  open problem about the linearity of -type spaces. Secondly, we introduce the conditions on so that the components of prequasi ideal are complete and closed. Thirdly, we investigate the sufficient settings on such that is strictly included for different weights and powers. We investigate the conditions for which the prequasi ideal is minimum. Fourthly, we explore the setting for which the Banach prequasi ideal is simple. Fifthly, we examine the sufficient setting on such that the class which sequence of eigenvalues in equals . In Section 7, the existence of a fixed point of Kannan prequasi norm contraction mapping on this sequence space and on its prequasi operator ideal generated by , and -numbers are presented. Additionally, in Section 8, we illustrate our results by some examples and applications to the existence of solutions of nonlinear difference equations. Finally, we introduce our conclusion in Section 9.
2. Definitions and Preliminaries
Lemma 3 . Assume and , then there exist operators and such that , for all .
Definition 4 . A Banach space is called simple if the algebra contains one and only one nontrivial closed ideal.
Theorem 5 . If is a Banach space with , hence
Definition 6 . An operator is called Fredholm if , , and is closed, where indicates the complement of .
Definition 7 . A class is called an operator ideal if each element verifies the following conditions: (i), if indicates Banach space of one dimension(ii) is a linear space on (iii)Assume , , and , then , where and are normed spaces
Definition 8 . A map is called a prequasi norm on the operator ideal , if it satisfies the following conditions: (1)For every , and (2)One has such that , with and (3)One has such that , for all (4)One has such that if , , and hence
Theorem 9 . Every quasi norm on the ideal is a prequasi norm on the same ideal.
Definition 10 . The linear space of sequences is called a private sequence space , if it verifies the next setup: (1), with (2) is solid, i.e., for , , and , with , then (3), where indicates the integral part of , if
Theorem 11 . Suppose the linear sequence space be a , then be an operator ideal.
Definition 12 . A subspace of the is called a premodular , if there exists a map verifies the next setup: (i)For all , , and , with is the zero vector of (ii)Assume and , one has with (iii) includes for some , with (iv)If , , one has (v)The inequality, holds, for (vi), where indicates the space of all sequences with finite none zero coordinates(vii)There are such that , with
Theorem 14 . Every premodular is a prequasi normed .
Theorem 15 . The function is a prequasi norm on , where , for all , whenever is a premodular .
Definition 16 . A prequasi norm on satisfies the Fatou property, if for each sequence with and all then
Definition 17 . A prequasi norm on the ideal , where , satisfies the Fatou property if for each sequence with and all , then
Definition 18. for all .
An element is called a fixed point of , if
Definition 19 . An operator is named a Kannan -contraction, if there exists , so as to for all .
Definition 20 . If is a prequasi normed (), and The operator is called -sequentially continuous at , if and only if, when then .
Definition 21 . For the prequasi norm on the ideal , where , , and The operator is called -sequentially continuous at , if and only if, when , then .
Definition 22 . If and is a prequasi normed . The operator is called a multiplication operator on , when , with . The multiplication operator is called created by , if .
Theorem 23 . Assume -type If is an operator ideal, then the next setups are confirmed: (1) -type (2)Suppose -type and -type , then -type (3)Assume and -type , then -type (4)The sequence space is solid, i.e., if -type and , for all and , then -type
3. Main Results
3.1. The Sequence Space
The definition and some inclusion relations of the sequence space under the function in this section are presented.
Definition 24. Suppose , where be the space of all sequences of positive reals. The sequence space with the function is evident by:
Theorem 25. Assume , one has
Proof. Assume , one has
Theorem 27. Pick up and , then be nonabsolute type.
Proof. Let , then . One has
Hence, the sequence space is nonabsolute type.
Note that, we call the sequence space as -generalized Cesàro sequence space of nonabsolute type since it is generated by the domain of -Cesàro matrix in , where the -Cesàro matrix, , is defined as: The -Cesàro matrix may be shown clearly as:
Definition 28. Pick up . The -generalized Cesàro sequence space of absolute type is defined as:
Theorem 29. Assume with , then .
Proof. Suppose , as Therefore, For , we take ; we have and . For , we take ; we have and .
4. Premodular Private Sequence Space
In this section, we investigate the sufficient conditions on with definite function to form premodular , which gives that is a prequasi normed .
Here and after, the space of all monotonic decreasing and monotonic increasing sequences of positive reals will be indicated by and , respectively.
Theorem 30. is a , if the following conditions are satisfied:
(f2) with or , and there exists such that
Proof. (1-i)Let . We havetherefore, .
(1-ii)Assume , and since , one hasTherefore, . According to conditions (1-i) and (1-ii), one has is a linear space.
Since and , we have Hence, , for all . (1)Assume , with and . We getthen . (2)Suppose , with and there exists with , one hasthen .
From Theorem 11, one has the following theorem.
Theorem 31. If the conditions (f1) and (f2) are confirmed, then is an operator ideal.
Theorem 32. is a premodular , if the conditions (f1) and (f2) are verified.
Proof. (i)Clearly, and (ii)One has with , for each and (iii)The inequality holds, with (iv)Obviously, from the proof part (31) of Theorem 30(v)Clearly, the proof part (32) of Theorem 30 that (vi)Definitely, (vii)There is with