Pub Date : 2020-01-01DOI: 10.5666/KMJ.2020.60.1.197
Anil Sharma
In this paper, we prove that there are no non-trivial PR-semi-slant warped product submanifolds with proper slant coefficients in para-Kähler manifolds M . We also present a numerical example that illustrates the existence of a PR-warped product submanifold in M .
{"title":"Non Existence of ℛ-semi-slant Warped Product Submanifolds in a Para-Kähler Manifold","authors":"Anil Sharma","doi":"10.5666/KMJ.2020.60.1.197","DOIUrl":"https://doi.org/10.5666/KMJ.2020.60.1.197","url":null,"abstract":"In this paper, we prove that there are no non-trivial PR-semi-slant warped product submanifolds with proper slant coefficients in para-Kähler manifolds M . We also present a numerical example that illustrates the existence of a PR-warped product submanifold in M .","PeriodicalId":46188,"journal":{"name":"Kyungpook Mathematical Journal","volume":"60 1","pages":"197-210"},"PeriodicalIF":0.7,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70850215","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.5666/KMJ.2020.60.4.831
N. Sayari
{"title":"Klein Bottles and Dehn Filling on a Component of Twocomponent Link Exterior","authors":"N. Sayari","doi":"10.5666/KMJ.2020.60.4.831","DOIUrl":"https://doi.org/10.5666/KMJ.2020.60.4.831","url":null,"abstract":"","PeriodicalId":46188,"journal":{"name":"Kyungpook Mathematical Journal","volume":"60 1","pages":"831-837"},"PeriodicalIF":0.7,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70849984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.5666/KMJ.2020.60.3.467
R. Sharafdini, A. Ghalavand, A. Ashrafi
Let G be a chemical graph with vertex set {v1, v1, . . . , vn} and degree sequence d(G) = (degG(v1), degG(v2), . . . , degG(vn)). The inverse degree, R(G) of G is defined as R(G) = ∑n i=1 1 degG(vi) . The cyclomatic number of G is defined as γ = m − n + k, where m, n and k are the number of edges, vertices and components of G, respectively. In this paper, some upper bounds on the diameter of a chemical graph in terms of its inverse degree are given. We also obtain an ordering of connected chemical graphs with respect to the inverse degree.
{"title":"On Diameter, Cyclomatic Number and Inverse Degree of Chemical Graphs","authors":"R. Sharafdini, A. Ghalavand, A. Ashrafi","doi":"10.5666/KMJ.2020.60.3.467","DOIUrl":"https://doi.org/10.5666/KMJ.2020.60.3.467","url":null,"abstract":"Let G be a chemical graph with vertex set {v1, v1, . . . , vn} and degree sequence d(G) = (degG(v1), degG(v2), . . . , degG(vn)). The inverse degree, R(G) of G is defined as R(G) = ∑n i=1 1 degG(vi) . The cyclomatic number of G is defined as γ = m − n + k, where m, n and k are the number of edges, vertices and components of G, respectively. In this paper, some upper bounds on the diameter of a chemical graph in terms of its inverse degree are given. We also obtain an ordering of connected chemical graphs with respect to the inverse degree.","PeriodicalId":46188,"journal":{"name":"Kyungpook Mathematical Journal","volume":"60 1","pages":"467-475"},"PeriodicalIF":0.7,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70850310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.5666/KMJ.2020.60.3.535
A. Devgan, R. K. Nagaich
In this paper, we introduce the geometry of contact CR submanifolds and radical transversal lightlike submanifolds of Sasaki-like almost contact manifolds with Bmetric. We obtain some new results that establish a relationship between these two submanifolds.
{"title":"Submanifolds of Sasaki-like Almost Contact Manifolds with B-metric","authors":"A. Devgan, R. K. Nagaich","doi":"10.5666/KMJ.2020.60.3.535","DOIUrl":"https://doi.org/10.5666/KMJ.2020.60.3.535","url":null,"abstract":"In this paper, we introduce the geometry of contact CR submanifolds and radical transversal lightlike submanifolds of Sasaki-like almost contact manifolds with Bmetric. We obtain some new results that establish a relationship between these two submanifolds.","PeriodicalId":46188,"journal":{"name":"Kyungpook Mathematical Journal","volume":"60 1","pages":"535-549"},"PeriodicalIF":0.7,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70850328","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.5666/KMJ.2020.60.1.117
M. Abolfathi, A. Ebadian
In this paper, we first introduce new classes of Lipschitz algebras of infinitely differentiable functions which are extensions of the standard Lipschitz algebras of infinitely differentiable functions. Then we determine the maximal ideal space of these extended algebras. Finally, we show that if X and K are uniformly regular subsets in the complex plane, then R(X,K) is natural.
{"title":"The Maximal Ideal Space of Extended Differentiable Lipschitz Algebras","authors":"M. Abolfathi, A. Ebadian","doi":"10.5666/KMJ.2020.60.1.117","DOIUrl":"https://doi.org/10.5666/KMJ.2020.60.1.117","url":null,"abstract":"In this paper, we first introduce new classes of Lipschitz algebras of infinitely differentiable functions which are extensions of the standard Lipschitz algebras of infinitely differentiable functions. Then we determine the maximal ideal space of these extended algebras. Finally, we show that if X and K are uniformly regular subsets in the complex plane, then R(X,K) is natural.","PeriodicalId":46188,"journal":{"name":"Kyungpook Mathematical Journal","volume":"60 1","pages":"117-125"},"PeriodicalIF":0.7,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70850151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.5666/KMJ.2020.60.3.445
F. Fatahi, R. Safakish
Let R be a commutative semiring with identity and M be a unitary Rsemimodule. Let φ : S(M) → S(M) ∪ {∅} be a function, where S(M) is the set of all subsemimodules of M . A proper subsemimodule N of M is called φ-prime subsemimodule, if r ∈ R and x ∈M with rx ∈ N φ(N) implies that r ∈ (N :R M) or x ∈ N . So if we take φ(N) = ∅ (resp., φ(N) = {0}), a φ-prime subsemimodule is prime (resp., weakly prime). In this article we study the properties of several generalizations of prime subsemimodules.
{"title":"prime Subsemimodules of Semimodules over Commutative Semirings","authors":"F. Fatahi, R. Safakish","doi":"10.5666/KMJ.2020.60.3.445","DOIUrl":"https://doi.org/10.5666/KMJ.2020.60.3.445","url":null,"abstract":"Let R be a commutative semiring with identity and M be a unitary Rsemimodule. Let φ : S(M) → S(M) ∪ {∅} be a function, where S(M) is the set of all subsemimodules of M . A proper subsemimodule N of M is called φ-prime subsemimodule, if r ∈ R and x ∈M with rx ∈ N φ(N) implies that r ∈ (N :R M) or x ∈ N . So if we take φ(N) = ∅ (resp., φ(N) = {0}), a φ-prime subsemimodule is prime (resp., weakly prime). In this article we study the properties of several generalizations of prime subsemimodules.","PeriodicalId":46188,"journal":{"name":"Kyungpook Mathematical Journal","volume":"60 1","pages":"445-453"},"PeriodicalIF":0.7,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70850449","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.5666/KMJ.2020.60.1.163
Murat Gevgeşoğlu, Y. Bolat
Difference equations are the discrete analogues of differential equations and they usually describe certain phenomena over the course of time. Difference equations have many applications in a wide variety of disciplines, such as economics, mathematical biology, social sciences and physics. We refer to [1, 2, 4, 6] for the basic theory and some applications of difference equations. Volterra difference equations are extensively used to model phenomena in engineering, economics, and in the natural and social sciences; their stability has been studied by many authors. In [5], Khandaker and Raffoul considered a Volterra discrete system with nonlinear perturbation
{"title":"Stability Criterion for Volterra Type Delay Difference Equations Including a Generalized Difference Operator","authors":"Murat Gevgeşoğlu, Y. Bolat","doi":"10.5666/KMJ.2020.60.1.163","DOIUrl":"https://doi.org/10.5666/KMJ.2020.60.1.163","url":null,"abstract":"Difference equations are the discrete analogues of differential equations and they usually describe certain phenomena over the course of time. Difference equations have many applications in a wide variety of disciplines, such as economics, mathematical biology, social sciences and physics. We refer to [1, 2, 4, 6] for the basic theory and some applications of difference equations. Volterra difference equations are extensively used to model phenomena in engineering, economics, and in the natural and social sciences; their stability has been studied by many authors. In [5], Khandaker and Raffoul considered a Volterra discrete system with nonlinear perturbation","PeriodicalId":46188,"journal":{"name":"Kyungpook Mathematical Journal","volume":"60 1","pages":"163-175"},"PeriodicalIF":0.7,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70850166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.5666/KMJ.2019.59.2.225
I. Jung, E. Ko, C. Pearcy
In a previous paper, the authors of this paper studied 2× 2 matrices in upper triangular form, whose entries are operators on Hilbert spaces, and in which the the (1, 1) entry has a nontrivial hyperinvariant subspace. We were able to show, in certain cases, that the 2× 2 matrix itself has a nontrivial hyperinvariant subspace. This generalized two earlier nice theorems of H. J. Kim from 2011 and 2012, and made some progress toward a solution of a problem that has been open for 45 years. In this paper we continue our investigation of such 2 × 2 operator matrices, and we improve our earlier results, perhaps bringing us closer to the resolution of the long-standing open problem, as mentioned above.
{"title":"Hyperinvariant subspaces for some 2 × 2 operator matrices, II","authors":"I. Jung, E. Ko, C. Pearcy","doi":"10.5666/KMJ.2019.59.2.225","DOIUrl":"https://doi.org/10.5666/KMJ.2019.59.2.225","url":null,"abstract":"In a previous paper, the authors of this paper studied 2× 2 matrices in upper triangular form, whose entries are operators on Hilbert spaces, and in which the the (1, 1) entry has a nontrivial hyperinvariant subspace. We were able to show, in certain cases, that the 2× 2 matrix itself has a nontrivial hyperinvariant subspace. This generalized two earlier nice theorems of H. J. Kim from 2011 and 2012, and made some progress toward a solution of a problem that has been open for 45 years. In this paper we continue our investigation of such 2 × 2 operator matrices, and we improve our earlier results, perhaps bringing us closer to the resolution of the long-standing open problem, as mentioned above.","PeriodicalId":46188,"journal":{"name":"Kyungpook Mathematical Journal","volume":"59 1","pages":"225-231"},"PeriodicalIF":0.7,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70850105","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.5666/KMJ.2020.60.4.853
Radhika Manghat, S. Siddabasappa
{"title":"MHD Boundary Layer Flow and Heat Transfer of Rotating Dusty Nanofluid over a Stretching Surface","authors":"Radhika Manghat, S. Siddabasappa","doi":"10.5666/KMJ.2020.60.4.853","DOIUrl":"https://doi.org/10.5666/KMJ.2020.60.4.853","url":null,"abstract":"","PeriodicalId":46188,"journal":{"name":"Kyungpook Mathematical Journal","volume":"68 1","pages":"853-867"},"PeriodicalIF":0.7,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70849999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.5666/KMJ.2020.60.4.797
Guowei Zhang, Jianming Qi
The Brück conjecture is still open for an entire function f with hyper order of no less than 1/2, which is not an integer. In this paper, it is proved that the hyper order of solutions of a linear complex differential equation that is related to the Brück Conjecture is infinite. The results show that the conjecture holds in a special case when the hyper order of f is 1/2.
{"title":"The Infinite Hyper Order of Solutions of Differential Equation Related to Brück Conjecture","authors":"Guowei Zhang, Jianming Qi","doi":"10.5666/KMJ.2020.60.4.797","DOIUrl":"https://doi.org/10.5666/KMJ.2020.60.4.797","url":null,"abstract":"The Brück conjecture is still open for an entire function f with hyper order of no less than 1/2, which is not an integer. In this paper, it is proved that the hyper order of solutions of a linear complex differential equation that is related to the Brück Conjecture is infinite. The results show that the conjecture holds in a special case when the hyper order of f is 1/2.","PeriodicalId":46188,"journal":{"name":"Kyungpook Mathematical Journal","volume":"60 1","pages":"797-803"},"PeriodicalIF":0.7,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70850381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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