Novi Sad Journal of Mathematics最新文献

{"title":"On the inclusion submodule graph of a module","authors":"Lotf Ali Mahdavić, Yahya Talebić","doi":"10.30755/nsjom.10828","DOIUrl":"https://doi.org/10.30755/nsjom.10828","url":null,"abstract":"","PeriodicalId":38723,"journal":{"name":"Novi Sad Journal of Mathematics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44485645","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}

{"title":"On some inequalities for double and path integrals on general domainsfootnote{Dedicated to Sienna and Audrey","authors":"S. Dragomir","doi":"10.30755/nsjom.11914","DOIUrl":"https://doi.org/10.30755/nsjom.11914","url":null,"abstract":"In this paper, by the use of the celebrated Green’s identity for double and path integrals, we establish some integral inequalities for functions of two variables de\u0085ned on closed and bounded subsets of the plane R2: Some examples for rectangles and disks are also provided. 1. Introduction In paper [1], the authors obtained among others the following results concerning the di¤erence between the double integral on the disk and the values in the center or the path integral on the circle: Theorem 1. If f : D (C;R) ! R has continuous partial derivatives on D (C;R) ; the disk centered in the point C = (a; b) with the radius R > 0; and @f @x D(C;R);1 : = sup (x;y)2D(C;R) @f (x; y) @x <1; @f @y D(C;R);1 : = sup (x;y)2D(C;R) @f (x; y) @y <1; then (1.1) f (C) 1 R2 ZZ D(C;R) f (x; y) dx dy 4 3 R \" @f @x D(C;R);1 + @f @y D(C;R);1 # : The constant 4 3 is sharp. We also have (1.2) 1 R2 ZZ D(C;R) f (x; y) dx dy 1 2 R Z (C;R) f ( ) dl ( ) 2R 3 \" @f @x D(C;R);1 + @f @y D(C;R);1 # ; 1991 Mathematics Subject Classi\u0085cation. 26D15. Key words and phrases. Double integral, Path integral, Green’s identity, Integral inequalities. 1 2 S. S. DRAGOMIR where (C;R) is the circle centered in C = (a; b) with the radius R > 0 and (1.3) f (C) 1 2 R Z (C;R) f ( ) dl ( ) 2R \" @f @x D(C;R);1 + @f @y D(C;R);1 # : In the same paper [1] the authors also established the following Ostrowski type inequality: Theorem 2. If f has bounded partial derivatives on D(0; 1), then (1.4) f (u; v) 1 ZZ D(0;1) f (x; y) dx dy 2 \" @f @x D(0;1);1 u arcsinu+ 1 3 p 1 u2 (2 + u) + @f @y D(0;1);1 v arcsin v + 1 3 p 1 v2 (2 + v) # for any (u; v) 2 D (0; 1). For other integral inequalities for double integrals see [2]-[14]. In this paper, by the use of the celebrated Green’s identity for double and path integrals, we establish some integral inequalities for functions of two variables de\u0085ned on closed and bounded subsets of the plane R: Some examples for rectangles and disks are also provided. 2. Main Results Let @D be a simple, closed counterclockwise curve in the xy-plane, bounding a region D. Let L and M be scalar functions de\u0085ned at least on an open set containing D. Assume L and M have continuous \u0085rst partial derivatives. Then the following equality is well known as the Green theorem (see for instance https://en.wikipedia.org/wiki/Green%27s_theorem) (G) Z Z D @M (x; y) @x @L (x; y) @y dxdy = I @D (L (x; y) dx+M (x; y) dy) : Moreover, if the curve @D is described by the function r (t) = (x (t) ; y (t)) ; t 2 [a; b] ; with x, y di¤erentiable on (a; b) then we can calculate the path integral as I @D (L (x; y) dx+M (x; y) dy) = Z b a [L (x (t) ; y (t))x0 (t) +M (x (t) ; y (t)) y0 (t)] dt: By applying this equality for real and imaginary parts, we can also state it for complex valued functions P and Q: INEQUALITIES FOR DOUBLE AND PATH INTEGRALS 3 For a function f : D ! C having partial derivatives on the domain D we de\u0085ne @f;D : D ! C as @f;D (x; y) := (x y) @f (x; y) @x @f (x; y) @y : We need the following i","PeriodicalId":38723,"journal":{"name":"Novi Sad Journal of Mathematics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44640392","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}

{"title":"Hyperspheres in Euclidean and Minkowski 4-spaces\u0000as almost paracontact almost paracomplex Riemannian manifolds","authors":"M. Manev, Veselina Tavkova","doi":"10.30755/nsjom.12136","DOIUrl":"https://doi.org/10.30755/nsjom.12136","url":null,"abstract":"Almost paracontact almost paracomplex Riemannian manifolds of the lowest dimension are studied. Such structures are constructed on hyperspheres in 4-dimensional spaces, Euclidean and pseudo-Euclidean, respectively. The obtained manifolds are studied and characterised in terms of the classification used and their geometric properties.","PeriodicalId":38723,"journal":{"name":"Novi Sad Journal of Mathematics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47564506","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}

{"title":"On a connection between fuzzy subgroups and $F$-inverse covers of inverse monoids","authors":"Elton Pasku","doi":"10.30755/nsjom.12394","DOIUrl":"https://doi.org/10.30755/nsjom.12394","url":null,"abstract":"We define two categories, the category $mathfrak{F}mathfrak{G}$ of fuzzy subgroups, and the category $mathfrak{F}mathfrak{C}$ of $F$-inverse covers of inverse monoids, and prove that $mathfrak{F}mathfrak{G}$ fully embeds into $mathfrak{F}mathfrak{C}$. This shows that, at least from a categorical viewpoint, fuzzy subgroups belong to the standard mathematics as much as they do to the fuzzy one.","PeriodicalId":38723,"journal":{"name":"Novi Sad Journal of Mathematics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48907207","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}

{"title":"Some characterizations of regularity and intra-regularity of $Gamma$-semigroups by means of quasi-ideals","authors":"Fabiana Çullhaj, Anjeza Krakulli","doi":"10.30755/nsjom.10795","DOIUrl":"https://doi.org/10.30755/nsjom.10795","url":null,"abstract":"The concept of regularity in Γ-semigroups is not very easy to deal with even though it shares some analogy with its analogue of semigroup theory. In this paper we establish a mechanism which translates the regularity in a Γ-semigroup (S,Γ) as the usual von Neumann regularity in an ordinary semigroup Ωγ0 that we construct in terms of (S,Γ). This enables us to characterize the regularity in Γ-semigroups by means of quasi-ideals. A similar characterization is proved for those Γ-semigroups which are regular and intra-regular. AMS Mathematics Subject Classification (2010): 20M05, 20M10, 20M12, 20M17","PeriodicalId":38723,"journal":{"name":"Novi Sad Journal of Mathematics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44126771","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}

{"title":"A note on $(m,n)^*$-paranormal operators","authors":"S. Ram, P. Dharmarha","doi":"10.30755/nsjom.10257","DOIUrl":"https://doi.org/10.30755/nsjom.10257","url":null,"abstract":"","PeriodicalId":38723,"journal":{"name":"Novi Sad Journal of Mathematics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44492667","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}

{"title":"Some properties of almost Jordan homomorphisms on Fréchet algebras","authors":"A. Zivari-kazempour","doi":"10.30755/nsjom.10382","DOIUrl":"https://doi.org/10.30755/nsjom.10382","url":null,"abstract":"","PeriodicalId":38723,"journal":{"name":"Novi Sad Journal of Mathematics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42273993","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}

{"title":"Atoms and coatoms in three-generated lattices","authors":"G'abor Cz'edli","doi":"10.30755/nsjom.12402","DOIUrl":"https://doi.org/10.30755/nsjom.12402","url":null,"abstract":"In addition to the unique cover $M^+$ of the variety of modular lattices, we also deal with those twenty-three known covers of $M^+$ that can be extracted from the literature. For $M^+$ and for each of these twenty-three known varieties covering it, we determine what the pair formed by the number of atoms and that of coatoms of a three-generated lattice belonging to the variety in question can be. Furthermore, for each variety $W$ of lattices that is obtained by forming the join of some of the twenty-three varieties mentioned above, that is, for $2^{23}$ possible choices of $W$, we determine how many atoms a three-generated lattice belonging to $W$ can have. The greatest number of atoms occurring in this way is only six. In order to point out that this need not be so for larger varieties, we construct a $47,092$-element three-generated lattice that has exactly eighteen atoms. In addition to purely lattice theoretical proofs, which constitute the majority of the paper, some computer-assisted arguments are also presented.","PeriodicalId":38723,"journal":{"name":"Novi Sad Journal of Mathematics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47031294","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}

{"title":"On generalized weakly (Ricci) $phi $-symmetric Lorentzian Para\u0000Sasakian manifold","authors":"M. R. Bakshi, K. Baishya, Dr. Ashis Biswas","doi":"10.30755/nsjom.11043","DOIUrl":"https://doi.org/10.30755/nsjom.11043","url":null,"abstract":"The present paper attempt to introduce the notion of generalized weakly φ-symmetric and generalized weakly Ricci φ-symmetric Lorentzian Para Sasakian manifold. Furthermore, we have studied generalized weakly φ-symmetric Lorentzian Para-Sasakian spacetimes. In addition, the existence of generalized weakly φ-symmetric Lorentzian Para Sasakian manifold is ensured by a suitable example. AMS Mathematics Subject Classification (2010): 53C15; 53C25","PeriodicalId":38723,"journal":{"name":"Novi Sad Journal of Mathematics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49514193","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}

{"title":"General iterative methods for common fixed points of asymptotically nonexpansive mappings","authors":"G. C. Ugwunnadi","doi":"10.30755/nsjom.10799","DOIUrl":"https://doi.org/10.30755/nsjom.10799","url":null,"abstract":"","PeriodicalId":38723,"journal":{"name":"Novi Sad Journal of Mathematics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43670346","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}