J. Oguntuase, L. Persson, O. Fabelurin, A. G. Adeagbo-Sheikh
Refinements of some limit Hardy-type inequalities are derived anddiscussed using the concept of superquadracity. We also proved that all threeconstants appearing in the refined inequalities obtaine ...
{"title":"Refinements of some limit Hardy-type inequalities via superquadracity","authors":"J. Oguntuase, L. Persson, O. Fabelurin, A. G. Adeagbo-Sheikh","doi":"10.2298/PIM1716231O","DOIUrl":"https://doi.org/10.2298/PIM1716231O","url":null,"abstract":"Refinements of some limit Hardy-type inequalities are derived anddiscussed using the concept of superquadracity. We also proved that all threeconstants appearing in the refined inequalities obtaine ...","PeriodicalId":416273,"journal":{"name":"Publications De L'institut Mathematique","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126367503","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}
In 2006, Vasil'ev posed the problem: Does there exist a positive integer k such that there are no k pairwise nonisomorphic nonabelian finite simple groups with the same graphs of primes? Conjecture: k = 5. In 2013, Zvezdina, confirmed the conjecture for the case when one of the groups is alternating. We continue this work and determine all nonabelian simple groups having the same prime graphs as the nonabelian simple group 2Dn(q).
{"title":"Simple groups with the same prime graph as 2Dn(q)","authors":"B. Khosravi, A. Babai","doi":"10.2298/PIM150304024K","DOIUrl":"https://doi.org/10.2298/PIM150304024K","url":null,"abstract":"In 2006, Vasil'ev posed the problem: Does there exist a positive integer k \u0000 such that there are no k pairwise nonisomorphic nonabelian finite simple \u0000 groups with the same graphs of primes? Conjecture: k = 5. In 2013, Zvezdina, \u0000 confirmed the conjecture for the case when one of the groups is alternating. \u0000 We continue this work and determine all nonabelian simple groups having the \u0000 same prime graphs as the nonabelian simple group 2Dn(q).","PeriodicalId":416273,"journal":{"name":"Publications De L'institut Mathematique","volume":"98 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130654361","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}
I. Dimitrijevic, B. Dragovich, J. Grujić, Z. Rakić
We consider a new modified gravity model with nonlocal term of the form R−1F(□)R. This kind of nonlocality is motivated by investigation of applicability of a few unusual ansatze to obtain some exact cosmological solutions. In particular, we find attractive and useful quadratic ansatz □R = qR2.
{"title":"A New Model of Nonlocal Modified Gravity","authors":"I. Dimitrijevic, B. Dragovich, J. Grujić, Z. Rakić","doi":"10.2298/PIM1308187D","DOIUrl":"https://doi.org/10.2298/PIM1308187D","url":null,"abstract":"We consider a new modified gravity model with nonlocal term of the form \u0000 R−1F(□)R. This kind of nonlocality is motivated by investigation of \u0000 applicability of a few unusual ansatze to obtain some exact cosmological \u0000 solutions. In particular, we find attractive and useful quadratic ansatz □R = \u0000 qR2.","PeriodicalId":416273,"journal":{"name":"Publications De L'institut Mathematique","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123088286","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}
We study the Schouten-van Kampen connection associated to an almost contact or paracontact metric structure. With the help of such a con- nection, some classes of almost (para) contact metric manifolds are character- ized. Certain curvature properties of this connection are found.
{"title":"The Schouten-van Kampen affine connection adapted to an almost (para) contact metric structure","authors":"Z. Olszak","doi":"10.2298/PIM1308031O","DOIUrl":"https://doi.org/10.2298/PIM1308031O","url":null,"abstract":"We study the Schouten-van Kampen connection associated to an almost contact or paracontact metric structure. With the help of such a con- nection, some classes of almost (para) contact metric manifolds are character- ized. Certain curvature properties of this connection are found.","PeriodicalId":416273,"journal":{"name":"Publications De L'institut Mathematique","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132178172","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}
We find the greatest value λ and the least value μ such that the double inequality C(λa +(1-λ)b, λb + (1-λ)a) < αA(a,b) + (1-α)T(a, b)< C(μa + (1-μ)b, μb + (1-μ)a) holds for all α (0,1) and a, b > 0 with a ≠ b, where C(a,b), A(a,b), and T(a,b) denote respectively the contraharmonic, arithmetic, and Toader means of two positive numbers a and b.
对于所有α(0,1)和a,b > 0且a≠b的情况下，λ的最大值和μ的最小值使得二重不等式C(λa +(1-λ)b， λb +(1-λ) a) < α a (a,b) +(1 -α)T(a, b)< C(μa +(1 -μ)b， μb +(1 -μ)a)成立，其中C(a,b)， a (a,b)和T(a,b)分别表示两个正数a和b的反调和、算术和Toader均值。
{"title":"A double inequality for the combination of Toader mean and the arithmetic mean in terms of the contraharmonic mean","authors":"Weidong Jiang, Feng Qi (祁锋)","doi":"10.2298/PIM141026009J","DOIUrl":"https://doi.org/10.2298/PIM141026009J","url":null,"abstract":"We find the greatest value λ and the least value μ such that the double \u0000 inequality C(λa +(1-λ)b, λb + (1-λ)a) < αA(a,b) + (1-α)T(a, b)< \u0000 C(μa + (1-μ)b, μb + (1-μ)a) holds for all α (0,1) and a, b > 0 with \u0000 a ≠ b, where C(a,b), A(a,b), and T(a,b) denote respectively the \u0000 contraharmonic, arithmetic, and Toader means of two positive numbers a and \u0000 b.","PeriodicalId":416273,"journal":{"name":"Publications De L'institut Mathematique","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122400858","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}
Geometry of confocal conics in the Minkowski plane and related billiard dynamics are studied in details. Periodic trajectories are described and several new examples are presented. Topological properties of the elliptical billiards are analyzed and the results are formulated in the terms of the Fomenko graphs. [Projekat Ministarstva nauke Republike Srbije, br. 174020: Geometry and Topology of Manifolds and Integrable Dynamical Systems]
{"title":"Minkowski plane, confocal conics, and billiards","authors":"V. Dragović, M. Radnović","doi":"10.2298/PIM1308017D","DOIUrl":"https://doi.org/10.2298/PIM1308017D","url":null,"abstract":"Geometry of confocal conics in the Minkowski plane and related billiard \u0000 dynamics are studied in details. Periodic trajectories are described and \u0000 several new examples are presented. Topological properties of the elliptical \u0000 billiards are analyzed and the results are formulated in the terms of the \u0000 Fomenko graphs. [Projekat Ministarstva nauke Republike Srbije, br. 174020: \u0000 Geometry and Topology of Manifolds and Integrable Dynamical Systems]","PeriodicalId":416273,"journal":{"name":"Publications De L'institut Mathematique","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127536499","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}
We investigate an infinite sequence of polynomials of the form: a0Tn(x) + a1Tn 1(x) + · · · + amTn m(x) where (a0, a1, . . . , am) is a fixed m-tuple of real numbers, a0, am 6 0, Ti(x) are Chebyshev polynomials of the first kind, n = m, m + 1, m + 2, . . . Here we analyze the structure of the set of zeros of such polynomial, depending on A and its limit points when n tends to infinity. Also the expression of envelope of the polynomial is given. An application in number theory, more precise, in the theory of Pisot and Salem numbers, is presented.
我们研究了形式为:a0Tn(x) + a1Tn 1(x) +···+ amTn m(x)的无穷多项式序列，其中(a0, a1，…， am)是实数的固定m元组，a0, am 6 0, Ti(x)是第一类Chebyshev多项式，n = m, m + 1, m + 2，…这里我们分析了这种多项式的零集的结构，这取决于A和当n趋于无穷时它的极限点。并给出了多项式包络线的表达式。在数论中，更准确地说，在Pisot数和Salem数的理论中，给出了一个应用。
{"title":"ON LINEAR COMBINATIONS OF CHEBYSHEV POLYNOMIALS","authors":"Dragan Stankov","doi":"10.2298/PIM150220001S","DOIUrl":"https://doi.org/10.2298/PIM150220001S","url":null,"abstract":"We investigate an infinite sequence of polynomials of the form: a0Tn(x) + a1Tn 1(x) + · · · + amTn m(x) where (a0, a1, . . . , am) is a fixed m-tuple of real numbers, a0, am 6 0, Ti(x) are Chebyshev polynomials of the first kind, n = m, m + 1, m + 2, . . . Here we analyze the structure of the set of zeros of such polynomial, depending on A and its limit points when n tends to infinity. Also the expression of envelope of the polynomial is given. An application in number theory, more precise, in the theory of Pisot and Salem numbers, is presented.","PeriodicalId":416273,"journal":{"name":"Publications De L'institut Mathematique","volume":"415 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126697394","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}
We prove several Tauberian theorems for regularizing transforms of vector-valued distributions. The regularizing transform of f is given by the integral transform M f(x, y) = (f � 'y)(x), (x, y) 2 R n × R+, with ker- nel 'y(t) = y−n'(t/y). We apply our results to the analysis of asymptotic stability for a class of Cauchy problems, Tauberian theorems for the Laplace transform, the comparison of quasiasymptotics in distribution spaces, and we give a necessary and sufficient condition for the existence of the trace of a dis- tribution on {x0} × R m . In addition, we present a new proof of Littlewood's Tauberian theorem.
证明了向量值分布正则化变换的几个Tauberian定理。f的正则化变换由积分变换M f(x, y) = (f′y)(x)， (x, y) 2r n × R+给出，其中ker- nel 'y(t) = y−n'(t/y)。将所得结果应用于一类Cauchy问题的渐近稳定性分析，拉普拉斯变换的Tauberian定理，分布空间中拟渐近性的比较，并给出了{x0} × R m上分布迹存在的充分必要条件。此外，我们给出了Littlewood的陶伯利定理的一个新的证明。
{"title":"MULTIDIMENSIONAL TAUBERIAN THEOREMS FOR VECTOR-VALUED DISTRIBUTIONS","authors":"S. Pilipovic, J. Vindas","doi":"10.2298/PIM1409001P","DOIUrl":"https://doi.org/10.2298/PIM1409001P","url":null,"abstract":"We prove several Tauberian theorems for regularizing transforms of vector-valued distributions. The regularizing transform of f is given by the integral transform M f(x, y) = (f � 'y)(x), (x, y) 2 R n × R+, with ker- nel 'y(t) = y−n'(t/y). We apply our results to the analysis of asymptotic stability for a class of Cauchy problems, Tauberian theorems for the Laplace transform, the comparison of quasiasymptotics in distribution spaces, and we give a necessary and sufficient condition for the existence of the trace of a dis- tribution on {x0} × R m . In addition, we present a new proof of Littlewood's Tauberian theorem.","PeriodicalId":416273,"journal":{"name":"Publications De L'institut Mathematique","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133238541","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}
We investigate the notion of λ-generalized contractions introduced by Ciric in uniform spaces endowed with a graph and discuss on the existence and uniqueness of fixed points for this type of contractions using the basic entourages.
{"title":"Fixed points for Ciric-G-contractions in uniform spaces endowed with a graph","authors":"A. Aghanians, K. Fallahi, K. Nourouzi, R. Verma","doi":"10.2298/PIM140202001A","DOIUrl":"https://doi.org/10.2298/PIM140202001A","url":null,"abstract":"We investigate the notion of λ-generalized contractions introduced by Ciric \u0000 in uniform spaces endowed with a graph and discuss on the existence and \u0000 uniqueness of fixed points for this type of contractions using the basic \u0000 entourages.","PeriodicalId":416273,"journal":{"name":"Publications De L'institut Mathematique","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125175522","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}
The group classification of variable coefficient quasilinearreaction- diffusion equations ut = uxx + h(x)B(u) is carried out exhaustively. This became possible due to usage of a conditional equivalence group found in the course of the study of admissible point transformations within the class.
{"title":"GROUP CLASSIFICATION OF VARIABLE COEFFICIENT QUASILINEAR REACTION-DIFFUSION EQUATIONS","authors":"O. Vaneeva, Alexander Zhalij","doi":"10.2298/PIM1308081V","DOIUrl":"https://doi.org/10.2298/PIM1308081V","url":null,"abstract":"The group classification of variable coefficient quasilinearreaction- diffusion equations ut = uxx + h(x)B(u) is carried out exhaustively. This became possible due to usage of a conditional equivalence group found in the course of the study of admissible point transformations within the class.","PeriodicalId":416273,"journal":{"name":"Publications De L'institut Mathematique","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134448291","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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