Research article

Nearly Menger covering property via bitopological spaces

  • Received: 28 October 2024 Revised: 24 November 2024 Accepted: 27 November 2024 Published: 03 December 2024
  • MSC : 54A10, 54D20, 54E55

  • This paper is a continuation and complement for previous works on selective covering properties. We introduce the novel concept of the nearly Menger property in a bitopological context. We demonstrate its interrelations with existing covering properties and construct certain equivalences between those. We also investigate various properties of nearly Menger bitopological spaces by considering it under subspaces, products, and certain type of mappings.

    Citation: Necati Can Açıkgöz, Ceren Sultan Elmalı. Nearly Menger covering property via bitopological spaces[J]. AIMS Mathematics, 2024, 9(12): 34042-34066. doi: 10.3934/math.20241623

    Related Papers:

    [1] Tingting Du, Zhengang Wu . Some identities of the generalized bi-periodic Fibonacci and Lucas polynomials. AIMS Mathematics, 2024, 9(3): 7492-7510. doi: 10.3934/math.2024363
    [2] Tingting Du, Zhengang Wu . Some identities involving the bi-periodic Fibonacci and Lucas polynomials. AIMS Mathematics, 2023, 8(3): 5838-5846. doi: 10.3934/math.2023294
    [3] Hong Kang . The power sum of balancing polynomials and their divisible properties. AIMS Mathematics, 2024, 9(2): 2684-2694. doi: 10.3934/math.2024133
    [4] Utkal Keshari Dutta, Prasanta Kumar Ray . On the finite reciprocal sums of Fibonacci and Lucas polynomials. AIMS Mathematics, 2019, 4(6): 1569-1581. doi: 10.3934/math.2019.6.1569
    [5] Waleed Mohamed Abd-Elhameed, Omar Mazen Alqubori . New expressions for certain polynomials combining Fibonacci and Lucas polynomials. AIMS Mathematics, 2025, 10(2): 2930-2957. doi: 10.3934/math.2025136
    [6] Kritkhajohn Onphaeng, Prapanpong Pongsriiam . Exact divisibility by powers of the integers in the Lucas sequence of the first kind. AIMS Mathematics, 2020, 5(6): 6739-6748. doi: 10.3934/math.2020433
    [7] Ala Amourah, B. A. Frasin, G. Murugusundaramoorthy, Tariq Al-Hawary . Bi-Bazilevič functions of order $ \vartheta +i\delta $ associated with $ (p, q)- $ Lucas polynomials. AIMS Mathematics, 2021, 6(5): 4296-4305. doi: 10.3934/math.2021254
    [8] Can Kızılateş, Halit Öztürk . On parametric types of Apostol Bernoulli-Fibonacci, Apostol Euler-Fibonacci, and Apostol Genocchi-Fibonacci polynomials via Golden calculus. AIMS Mathematics, 2023, 8(4): 8386-8402. doi: 10.3934/math.2023423
    [9] Abdulmtalb Hussen, Mohammed S. A. Madi, Abobaker M. M. Abominjil . Bounding coefficients for certain subclasses of bi-univalent functions related to Lucas-Balancing polynomials. AIMS Mathematics, 2024, 9(7): 18034-18047. doi: 10.3934/math.2024879
    [10] Waleed Mohamed Abd-Elhameed, Amr Kamel Amin, Nasr Anwer Zeyada . Some new identities of a type of generalized numbers involving four parameters. AIMS Mathematics, 2022, 7(7): 12962-12980. doi: 10.3934/math.2022718
  • This paper is a continuation and complement for previous works on selective covering properties. We introduce the novel concept of the nearly Menger property in a bitopological context. We demonstrate its interrelations with existing covering properties and construct certain equivalences between those. We also investigate various properties of nearly Menger bitopological spaces by considering it under subspaces, products, and certain type of mappings.



    Fibonacci polynomials and Lucas polynomials are important in various fields such as number theory, probability theory, numerical analysis, and physics. In addition, many well-known polynomials, such as Pell polynomials, Pell Lucas polynomials, Tribonacci polynomials, etc., are generalizations of Fibonacci polynomials and Lucas polynomials. In this paper, we extend the linear recursive polynomials to nonlinearity, that is, we discuss some basic properties of the bi-periodic Fibonacci and Lucas polynomials.

    The bi-periodic Fibonacci {fn(t)} and Lucas {ln(t)} polynomials are defined recursively by

    f0(t)=0,f1(t)=1,fn(t)={ayfn1(t)+fn2(t)n0(mod2),byfn1(t)+fn2(t)n1(mod2),n2,

    and

    l0(t)=2,l1(t)=at,ln(t)={byln1(t)+ln2(t)n0(mod2),ayln1(t)+ln2(t)n1(mod2),n2,

    where a and b are nonzero real numbers. For t=1, the bi-periodic Fibonacci and Lucas polynomials are, respectively, well-known bi-periodic Fibonacci {fn} and Lucas {ln} sequences. We let

    ς(n)={0n0(mod2),1n1(mod2),n2.

    In [1], the scholars give the Binet formulas of the bi-periodic Fibonacci and Lucas polynomials as follows:

    fn(t)=aς(n+1)(ab)n2(σn(t)τn(t)σ(t)τ(t)), (1.1)

    and

    ln(t)=aς(n)(ab)n+12(σn(t)+τn(t)), (1.2)

    where n0, σ(t), and τ(t) are zeros of λ2abtλab. This is σ(t)=abt+a2b2t2+4ab2 and τ(t)=abta2b2t2+4ab2. We note the following algebraic properties of σ(t) and τ(t):

    σ(t)+τ(t)=abt,σ(t)τ(t)=a2b2t2+4ab,σ(t)τ(t)=ab.

    Many scholars studied the properties of bi-periodic Fibonacci and Lucas polynomials; see [2,3,4,5,6]. In addition, many scholars studied the power sums problem of second-order linear recurrences and its divisible properties; see [7,8,9,10].

    Taking a=b=1 and t=1, we obtain the Fibonacci {Fn} or Lucas {Ln} sequence. Melham [11] proposed the following conjectures:

    Conjecture 1. Let m1 be an integer, then the sum

    L1L3L5L2m+1nk=1F2m+12k

    can be represented as (F2n+11)2R2m1(F2n+1), including R2m1(t) as a polynomial with integer coefficients of degree 2m1.

    Conjecture 2. Let m1 be an integer, then the sum

    L1L3L5L2m+1nk=1L2m+12k

    can be represented as (L2n+11)Q2m(L2n+1), where Q2m(t) is a polynomial with integer coefficients of degree 2m.

    In [12], the authors completely solved the Conjecture 2 and discussed the Conjecture 1. Using the definition and properties of bi-periodic Fibonacci and Lucas polynomials, the power sums problem and their divisible properties are studied in this paper. The results are as follows:

    Theorem 1. We get the identities

    nk=1f2m+12k(t)=a2m+1b(a2b2t2+4ab)mmj=0(1)mj(2m+1mj)(f(2n+1)(2j+1)(t)f2j+1(t)l2j+1(t)), (1.3)
    nk=1f2m+12k+1(t)=(ab)m(a2b2t2+4ab)mmj=0(2m+1mj)(f(2n+2)(2j+1)(t)f2(2j+1)(t)l2j+1(t)), (1.4)
    nk=1l2m+12k(t)=mj=0(2m+1mj)(l(2n+1)(2j+1)(t)l2j+1(t)l2j+1(t)), (1.5)
    nk=1l2m+12k+1(t)=am+1bm+1mj=0(1)mj(2m+1mj)(l(2n+2)(2j+1)(t)l2(2j+1)(t)l2j+1(t)), (1.6)

    where n and m are positive integers.

    Theorem 2. We get the identities

    nk=1f2m2k(t)=a2m(a2b2t2+4ab)mmj=0(1)mj(2mmj)f2j(2n+1)(t)f2j(t)a2m(a2b2t2+4ab)m(2mm)(1)m(n+12), (1.7)
    nk=1f2m2k+1(t)=(ab)m(a2b2t2+4ab)mmj=0(2mmj)(f2j(2n+2)(t)f4j(t)f2j(t))(ab)m(a2b2t2+4ab)m(2mm)n, (1.8)
    nk=1l2m2k(t)=mj=0(2mmj)f2j(2n+1)(t)l2j+1(t)22m1(2mm)(n+12), (1.9)
    nk=1l2m2k+1(t)=ambmmj=0(1)mj(2mmj)(f2j(2n+2)(t)f4j(t)f2j(t))ambm(2mm)(1)mn, (1.10)

    where n and m are positive integers.

    As for application of Theorem 1, we get the following:

    Corollary 1. We get the congruences:

    bl1(t)l3(t)l2m+1(t)nk=1f2m+12k(t)0(modf2n+1(t)1), (1.11)

    and

    al1(t)l3(t)l2m+1(t)nk=1l2m+12k(t)0(modl2n+1(t)at), (1.12)

    where n and m are positive integers.

    Taking t=1 in Corollary 1, we have the following conclusions for bi-periodic Fibonacci {fn} and Lucas {ln} sequences.

    Corollary 2. We get the congruences:

    bl1l3l2m+1nk=1f2m+12k0(modf2n+11), (1.13)

    and

    al1l3l2m+1nk=1l2m+12k0(modl2n+1a), (1.14)

    where n and m are nonzero real numbers.

    Taking a=b=1 and t=1 in Corollary 1, we have the following conclusions for bi-periodic Fibonacci {Fn} and Lucas {Ln} sequences.

    Corollary 3. We get the congruences:

    L1L3L2m+1nk=1F2m+12k0(modF2n+11), (1.15)

    and

    L1L3L2m+1nk=1L2m+12k0(modL2n+11), (1.16)

    where n and m are nonzero real numbers.

    To begin, we will give several lemmas that are necessary in proving theorems.

    Lemma 1. We get the congruence

    f(2n+1)(2j+1)(t)f2j+1(t)0(modf2n+1(t)1),

    where n and m are nonzero real numbers.

    Proof. We prove it by complete induction for j0. This clearly holds when j=0. If j=1, we note that abf3(2n+1)(t)=(a2b2t2+4ab)f32n+1(t)3abf2n+1(t) and we obtain

    f3(2n+1)(t)f3(t)=(abt2+4)f32n+1(t)3f2n+1(t)(abt2+4)f31(t)+3f1(t)=(abt2+4)(f2n+1(t)f1(t))(f22n+1(t)+f2n+1(t)f1(t)+f21(t))3(f2n+1(t)f1(t))=(abt2+4)(f2n+1(t)1)(f22n+1(t)+f2n+1(t)f1(t)+f21(t))3(f2n+1(t)1)0(modf2n+1(t)1).

    This is obviously true when j=1. Assuming that Lemma 1 holds if j=1,2,,k, that is,

    f(2n+1)(2j+1)(t)f2j+1(t)0(modf2n+1(t)1).

    If j=k+12, we have

    l2(2n+1)(t)f(2n+1)(2j+1)(t)=f(2n+1)(2j+3)(t)+abf(2n+1)(2j1)(t),

    and

    abl2(2n+1)(t)=(a2b2t2+4ab)f22n+1(t)2ab(a2b2t2+4ab)f21(t)2ab(modf2n+1(t)1).

    We have

    f(2n+1)(2k+3)(t)f2k+3(t)=l2(2n+1)(t)f(2n+1)(2k+1)(t)abf(2n+1)(2k1)(t)l2(t)f2k+1(t)+abf2k1(t)((abt2+4)f21(t)2)f(2n+1)(2k+1)(t)abf(2n+1)(2k1)(t)((abt2+4)f21(t)2)f2k+1(t)+abf2k1(t)((abt2+4)f21(t)2)(f(2n+1)(2k+1)(t)f2k+1(t))ab(f(2n+1)(2k1)(t)f2k1(t))0(modf2n+1(t)1).

    This completely proves Lemma 1.

    Lemma 2. We get the congruence

    al(2n+1)(2j+1)(t)al2j+1(t)0(modl2n+1(t)at),

    where n and m are nonzero real numbers.

    Proof. We prove it by complete induction for j0. This clearly holds when j=0. If j=1, we note that al3(2n+1)(t)=bl32n+1(t)+3al2n+1(t) and we obtain

    al3(2n+1)(t)al3(t)=bl32n+1(t)+3al2n+1(t)bl31(t)3al1(t)=(l2n+1(t)l1(t))(bl22n+1(t)+bl2n+1(t)l1(t)+bl21(t))3a(l2n+1(t)l1(t))=(l2n+1(t)at)(bl22n+1(t)+bayl2n+1(t)+ba2t2)3a(l2n+1(t)at)0(modl2n+1(t)at).

    This is obviously true when j=1. Assuming that Lemma 2 holds if j=1,2,,k, that is,

    al(2n+1)(2j+1)(t)al2j+1(t)0(modl2n+1(t)at).

    If j=k+12, we have

    l2(2n+1)(t)l(2n+1)(2j+1)(t)=l(2n+1)(2j+3)(t)+l(2n+1)(2j1)(t),

    and

    al2(2n+1)(t)=bl22n+1(t)+2abl21(t)+2a(modl2n+1(t)at).

    We have

    al(2n+1)(2k+3)(t)al(2k+3)(t)=a(l2(2n+1)(t)l(2n+1)(2k+1)(t)l(2n+1)(2k1)(t))a(l2(t)l2k+1(t)l2k1(t))(bl21(t)+2a)l(2n+1)(2k+1)(t)al(2n+1)(2k1)(t)(bl21(t)+2a)l2k+1(t)+al2k1(t)(abt2+2)(al(2n+1)(2k+1)(t)al2k+1(t))(al(2n+1)(2k1)(t)al2k1(t))0(modl2n+1(t)at).

    This completely proves Lemma 2.

    Proof of Theorem 1. We only prove (1.3), and the proofs for other identities are similar.

    nk=1f2m+12k(t)=nk=1(aς(2k+1)(ab)2k2(σ2k(t)τ2k(t)σ(t)τ(t)))2m+1=a2m+1(σ(t)τ(t))2m+1nk=1(σ2k(t)τ2k(t))2m+1(ab)(2m+1)k=a2m+1(σ(t)τ(t))2m+1nk=12m+1j=0(1)j(2m+1j)σ2k(2m+1j)(t)τ2kj(t)(ab)(2m+1)k=a2m+1(σ(t)τ(t))2m+12m+1j=0(1)j(2m+1j)(1σ2n(2m+12j)(t)(ab)(2m+12j)n(ab)2m+12jσ2(2m+12j)(t)1)=a2m+1(σ(t)τ(t))2m+1mj=0(1)j(2m+1j)(1σ2n(2m+12j)(t)(ab)(2m+12j)n(ab)2m+12jσ2(2m+12j)(t)11σ2n(2j12m)(t)(ab)(2j12m)n(ab)2j12mσ2(2j12m)(t)1)=a2m+1(σ(t)τ(t))2m+1mj=0(1)j(2m+1j)(σ2(2m+12j)(t)(ab)2m+12jσ(2n+2)(2m+12j)(t)(ab)(n+1)(2m+12j)+1σ2n(2j12m)(t)(ab)(2j12m)n1σ2(2m+12j)(t)(ab)(2m+12j))=a2m+1(σ(t)τ(t))2m+1mj=0(1)j(2m+1j)×(σ2m+12j(t)τ2m+12j(t)σ(2n+1)(2m+12j)(t)(ab)(2m+12j)n+τ(2n+1)(2m+12j)(t)(ab)(2m+12j)nσ2m+12j(t)τ2m+12j(t))=a2m+1b(a2b2t2+4ab)mmj=0(1)mj(2m+1mj)(f(2n+1)(2j+1)(t)f2j+1(t)l2j+1(t)).

    Proof of Theorem 2. We only prove (1.7), and the proofs for other identities are similar.

    nk=1f2m2k(t)=nk=1(aς(2k+1)(ab)2k2(σ2k(t)τ2k(t)σ(t)τ(t)))2m=a2m(σ(t)τ(t))2mnk=1(σ2k(t)τ2k(t))2m(ab)2mk=a2m(σ(t)τ(t))2mnk=12mj=0(1)j(2mj)σ2k(2mj)(t)τ2kj(t)(ab)2mk=a2m(σ(t)τ(t))2m2mj=0(1)j(2mj)(1σ2n(2m2j)(t)(ab)(2m2j)n(ab)2m2jσ2(2m2j)(t)1)
    =a2m(σ(t)τ(t))2mmj=0(1)j(2mj)(1σ2n(2m2j)(t)(ab)(2m2j)n(ab)2m2jσ2(2m2j)(t)1+1σ2n(2j2m)(t)(ab)(2j2m)n(ab)2j2mσ2(2j2m)(t)1)+a2m(σ(t)τ(t))2m(1)m+1(2mm)n=a2m(σ(t)τ(t))2mmj=0(1)j(2mj)(σ2(2m2j)(t)(ab)2m2jσ(2n+2)(2m2j)(t)(ab)(n+1)(2m2j)1+σ2n(2j2m)(t)(ab)(2j2m)n1σ2(2m2j)(t)(ab)2m2j)+a2m(σ(t)τ(t))2m(1)m+1(2mm)n=a2m(σ(t)τ(t))2mmj=0(1)j(2mj)(σ2m2j(t)τ2m2j(t)σ(2n+1)(2m2j)(t)(ab)n(2m2j)+τ(2n+1)(2m2j)(t)(ab)n(2m2j)τ2m2j(t)σ2m2j(t))+a2m(σ(t)τ(t))2m(1)m+1(2mm)n=a2m(a2b2t2+4ab)mmj=0(1)mj(2mmj)(f2j(2n+1)(t)f2j(t)f2j(t))+a2m(a2b2t2+4ab)m(1)m+1(2mm)n.

    Proof of Corollary 1. First, from the definition of fn(t) and binomial expansion, we easily prove (f2n+1(t)1,a2b2t2+4ab)=1. Therefore, (f2n+1(t)1,(a2b2t2+4ab)m)=1. Now, we prove (1.11) by Lemma 1 and (1.3):

    bl1(t)l3(t)l2m+1(t)nk=1f2m+12k(t)=l1(t)l3(t)l2m+1(t)(a2m+1(σ(t)τ(t))2mmj=0(1)mj(2m+1mj)(f(2n+1)(2j+1)(t)f2j+1(t)l2j+1(t)))0(modf2n+1(t)1).

    Now, we use Lemma 2 and (1.5) to prove (1.12):

    al1(t)l3(t)l2m+1(t)nk=1l2m+12k(t)=l1(t)l3(t)l2m+1(t)(mj=0(2m+1mj)(al(2n+1)(2j+1)(t)al2j+1(t)l2j+1(t)))0(modl2n+1(t)at).

    In this paper, we discuss the power sums of bi-periodic Fibonacci and Lucas polynomials by Binet formulas. As corollaries of the theorems, we extend the divisible properties of the sum of power of linear Fibonacci and Lucas sequences to nonlinear Fibonacci and Lucas polynomials. An open problem is whether we extend the Melham conjecture to nonlinear Fibonacci and Lucas polynomials.

    The authors declare that they did not use Artificial Intelligence (AI) tools in the creation of this paper.

    The authors would like to thank the editor and referees for their helpful suggestions and comments, which greatly improved the presentation of this work. All authors contributed equally to the work, and they have read and approved this final manuscript. This work is supported by Natural Science Foundation of China (12126357).

    The authors declare that there are no conflicts of interest regarding the publication of this paper.



    [1] W. Hurewicz, Über eine verallgemeinerung des Borelschen theorems, Math. Z., 24 (1926), 401–421. https://doi.org/10.1007/BF01216792 doi: 10.1007/BF01216792
    [2] K. Menger, Einige Uberdeckungssätze der Punktmengenlehren, Gedruckt Unterstutzung Jerome Margaret Stonborough, 133 (1924), 421–444.
    [3] M. Scheepers, Combinatorics of open covers Ⅰ: Ramsey theory, Topol. Appl., 69 (1996), 31–62. https://doi.org/10.1016/0166-8641(95)00067-4 doi: 10.1016/0166-8641(95)00067-4
    [4] W. Just, A. W. Miller, M. Scheepers, P. J. Szeptycki, The combinatorics of open covers Ⅱ, Topol. Appl., 73 (1996), 241–266. https://doi.org/10.1016/S0166-8641(96)00075-2 doi: 10.1016/S0166-8641(96)00075-2
    [5] M. Scheepers, Selection principles and covering properties in topology, Note Mat., 22 (2003), 3–41. https://doi.org/10.1285/I15900932V22N2P3 doi: 10.1285/I15900932V22N2P3
    [6] F. Rothberger, Eine verscharfung der eigenschaft c, Fund. Math., 30 (1938), 50–55. https://doi.org/10.4064/FM-30-1-50-55 doi: 10.4064/FM-30-1-50-55
    [7] T. Banakh, D. Repovš, Universal nowhere dense and meager sets in Menger manifolds, Topol. Appl., 161 (2014), 127–140. https://doi.org/10.1016/j.topol.2013.09.012 doi: 10.1016/j.topol.2013.09.012
    [8] D. Repovs, L. Zdomskyy, S. Zhang, Countable dense homogeneous filters and the Menger covering property, arXiv, 2014. https://doi.org/10.48550/arXiv.1406.0692
    [9] M. Scheepers, Selection principles and Baire spaces, Mat. Vesn., 61 (2009), 195–202.
    [10] D. Kocev, Almost Menger and related spaces, Mat. Vesn., 61 (2009), 173–180.
    [11] L. D. Kočinac, Star Menger and related spaces Ⅱ, Filomat, 13 (1999), 129–140.
    [12] L. D. Kočinac, Generalized open sets and selection properties, Filomat, 33 (2019), 1485–1493. https://doi.org/10.2298/fil1905485k doi: 10.2298/fil1905485k
    [13] L. D. Kočinac, T. M. Al-Shami, V. Çetkin, Selection principles in the context of soft sets: Menger spaces, Soft Comput., 25 (2021), 12693–12702. https://doi.org/10.1007/s00500-021-06069-6 doi: 10.1007/s00500-021-06069-6
    [14] T. M. Al-Shami, L. D. Kočinac, Nearly soft Menger spaces, J. Math., 2020 (2020), 3807418. https://doi.org/10.1155/2020/3807418 doi: 10.1155/2020/3807418
    [15] T. M. Al-Shami, L. D. Kočinac, Almost soft Menger and weakly soft Menger spaces, Appl. Comput. Math., 21 (2022), 35–51. https://doi.org/10.30546/1683-6154.21.1.2022.35 doi: 10.30546/1683-6154.21.1.2022.35
    [16] S. Özçağ, A. E. Eysen, Almost Menger property in bitopological spaces, Ukr. Math. J., 68 (2016), 950–958. https://doi.org/10.1007/s11253-016-1268-4 doi: 10.1007/s11253-016-1268-4
    [17] A. E. Eysen, S. Özçağ, Weaker forms of the Menger property in bitopological spaces, Quaest. Math., 41 (2018), 877–888.
    [18] A. E. Eysen, S. Özçağ, Investigations on weak versions of the Alster property in bitopological spaces and selection principles, Filomat, 33 (2019), 4561–4571. https://doi.org/10.2298/fil1914561E doi: 10.2298/fil1914561E
    [19] L. D. Kočinac, S. Özçağ, Versions of separability in bitopological spaces, Topol. Appl., 158 (2011), 1471–1477. https://doi.org/10.1016/j.topol.2011.05.019 doi: 10.1016/j.topol.2011.05.019
    [20] L. D. Kočinac, S. Özçağ, Bitopological spaces and selection principles, Proc. ICTA, 2011,243–255.
    [21] D. Lyakhovets, A. V. Osipov, Selection principles and games in bitopological function spaces, Filomat, 33 (2019), 4535–4540. https://doi.org/10.2298/fil1914535L doi: 10.2298/fil1914535L
    [22] A. V. Osipov, S. Özçağ, Variations of selective separability and tightness in function spaces with set-open topologies, Topol. Appl., 217 (2017), 38–50. https://doi.org/10.1016/j.topol.2016.12.010 doi: 10.1016/j.topol.2016.12.010
    [23] L. D. Kočinac, Variations of classical selection principles: an overview, Quaest. Math., 43 (2020), 1121–1153. https://doi.org/10.2989/16073606.2019.1601646 doi: 10.2989/16073606.2019.1601646
    [24] H. V. Chauhan, B. Singh, On almost Hurewicz property in bitopological spaces, Commun. Fac. Sci. Univ. Ank. Ser. A1 Math. Stat., 70 (2021), 74–81. https://doi.org/10.31801/cfsuasmas.710601 doi: 10.31801/cfsuasmas.710601
    [25] N. C. Açıkgöz, C. S. Elmalı, On almost set-Menger spaces in bitopological context, AIMS Math., 7 (2022), 20579–20593. https://doi.org/10.3934/math.20221128 doi: 10.3934/math.20221128
    [26] A. E. Eysen, S. Özçağ, Games relating to weak covering properties in bitopological spaces, Turk. J. Math., 44 (2020) 2297–2305. https://doi.org/10.3906/mat-2004-25 doi: 10.3906/mat-2004-25
    [27] R. Engelking, General topology, Berlin Heldermann, 1989.
    [28] B. P. Dvalishvili, Bitopological spaces: theory, relations with generalized algebraic structures, and applications, Elsevier, 2005. https://doi.org/10.1016/s0304-0208(05)x8090-2
    [29] A. Parvez, M. D. Khan, On nearly Menger and nearly star-Menger spaces, Filomat, 33 (2019), 6219–6227. https://doi.org/10.2298/fil1919219a doi: 10.2298/fil1919219a
    [30] L. A. Steen, J. A. Seebach, Counterexamples in topology, Dover Publication, 1995.
    [31] A. R. Singal, S. P. Arya, On pairwise almost regular spaces, Glasnik Math., 6 (1971), 335–343.
    [32] F. Commaroto, G. Santoro, Some counterexamples and properties on generalizations of Lindelöf spaces, Int. J. Math. Math. Sci., 19 (1996), 737–746. https://doi.org/10.1155/S0161171296001020 doi: 10.1155/S0161171296001020
    [33] M. K. Singal, A. R. Singal, Some more separation axioms in bitopological spaces, Ann. Son. Sci. Bruxelles, 84 (1970), 207–230.
    [34] A. Kilicman, Z. Salleh, On the pairwise weakly Lindelöf bitopological spaces, Bull. Iran. Math. Soc., 39 (2013), 469–486.
    [35] Z. Salleh, A. Kilicman, On pairwise nearly Lindelöf bitopological spaces, Far East J. Math. Sci., 77 (2013), 147–171.
    [36] S. N. Maheshwari, R. Prasad, Semi open sets and semi continuous function in bitopological spaces, Math. Notae, 26 (1977), 29–37.
    [37] F. H. Khedr, A. M. Alshibani, On pairwise supercontinuous mappings in bitopological spaces, Int. J. Math. Math. Sci., 14 (1991), 715–722. https://doi.org/10.1155/S0161171291000960 doi: 10.1155/S0161171291000960
    [38] M. C. Datta, Projective bitopological spaces Ⅱ, J. Aust. Math. Soc., 14 (1972), 119–128. https://doi.org/10.1017/S1446788700009708 doi: 10.1017/S1446788700009708
    [39] A. Lelek, Some cover properties of spaces, Fund. Math., 64 (1969), 209–218. https://doi.org/10.4064/FM-64-2-209-218 doi: 10.4064/FM-64-2-209-218
    [40] G. K. Banerjee, On pairwise almost strongly θ-continuous mappings, Bull. Cal. Math. Soc., 79 (1987), 314–320.
    [41] A. Sabah, M. D. Khan, L. D. Kočinac, Covering properties defined by semi-open sets, J. Nonlinear Sci. Appl., 9 (2016), 4388–4398. https://doi.org/10.22436/jnsa.009.06.79 doi: 10.22436/jnsa.009.06.79
    [42] M. Kule, Ş. Dost, β-selection properties in ditopological texture spaces, Sigma J. Eng. Nat. Sci., 38 (2020), 1019–1029.
    [43] F. H. Khedr, S. M. Al-Areefi, T. Noiri, Precontinuity and semi-precontinuity in bitopological spaces, Indian J. Pure Appl. Math., 23 (1992), 625–633.
    [44] M. Jelic, A decomposition of pairwise continuity, J. Inst. Math. Comput. Sci. Math. Ser., 3 (1990), 25–29.
    [45] S. S. Kumar, On decomposition of pairwise continuity, Bull. Cal. Math. Soc., 89 (1997), 441–446.
    [46] G. Thamizharasi, P. Thangavelu, Remarks on closure and interior operators in bitopological spaces, J. Math. Sci. Comput. Appl., 1 (2010), 1–8. https://doi.org/10.5147/jmsca.v1i1.85 doi: 10.5147/jmsca.v1i1.85
    [47] N. C. Açıkgöz, C. S. Elmalı, On the extension of SD sets by using generalized open sets in bitopological spaces, Int. J. Nonlinear Anal. Appl., 14 (2023), 1627–1638. https://doi.org/10.22075/ijnaa.2022.27884.3747 doi: 10.22075/ijnaa.2022.27884.3747
  • Reader Comments
  • © 2024 the Author(s), licensee AIMS Press. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0)
通讯作者: 陈斌, bchen63@163.com
  • 1. 

    沈阳化工大学材料科学与工程学院 沈阳 110142

  1. 本站搜索
  2. 百度学术搜索
  3. 万方数据库搜索
  4. CNKI搜索

Metrics

Article views(543) PDF downloads(80) Cited by(0)

Other Articles By Authors

/

DownLoad:  Full-Size Img  PowerPoint
Return
Return

Catalog