In this paper, first we study the harmonicity of the functions and forms on the twisted products, and then we determine its sectional curvature. We explore some characteristics of static perfect fluid and static vacuum spacetimes on twisted product manifolds by proving the existence and obstructions on Ricci curvature. Finally, we study the problem of the existence static perfect fluid spacetime associated with the twisted generalized Robertson-Walker and standard static spacetime metrics.
{"title":"Geometry of Twisted Products and Applications on Static Perfect Fluid Spacetimes","authors":"Sinem GÜLER, U.c. DE, Bülent ÜNAL","doi":"10.36890/iejg.1286525","DOIUrl":"https://doi.org/10.36890/iejg.1286525","url":null,"abstract":"In this paper, first we study the harmonicity of the functions and forms on the twisted products, and then we determine its sectional curvature. We explore some characteristics of static perfect fluid and static vacuum spacetimes on twisted product manifolds by proving the existence and obstructions on Ricci curvature. Finally, we study the problem of the existence static perfect fluid spacetime associated with the twisted generalized Robertson-Walker and standard static spacetime metrics.","PeriodicalId":43768,"journal":{"name":"International Electronic Journal of Geometry","volume":"59 17","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136133635","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 Ricci tensor field, $varphi$-Ricci tensor field and the characteristic Jacobi operator on almost Kenmotsu $3$-manifolds are investigated. We give a classification of locally symmetric almost Kenmotsu $3$-manifolds.
{"title":"Characteristic Jacobi operator on almost Kenmotsu $3-manifolds","authors":"Jun-ichi INOGUCHI","doi":"10.36890/iejg.1300339","DOIUrl":"https://doi.org/10.36890/iejg.1300339","url":null,"abstract":"The Ricci tensor field, $varphi$-Ricci tensor field and the characteristic Jacobi operator on almost Kenmotsu $3$-manifolds are investigated. We give a classification of locally symmetric almost Kenmotsu $3$-manifolds.","PeriodicalId":43768,"journal":{"name":"International Electronic Journal of Geometry","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136134465","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 mention some properties of statistical submanifolds in statistical manifolds of quasi-constant curvature. We obtain Chen first inequality and a Chen inequality for the $delta (2,2)$-invariant for these manifolds.
{"title":"On Statistical Submanifolds in Statistical Manifolds of Quasi-Constant Curvature","authors":"Hülya AYTİMUR","doi":"10.36890/iejg.1237417","DOIUrl":"https://doi.org/10.36890/iejg.1237417","url":null,"abstract":"We mention some properties of statistical submanifolds in statistical manifolds of quasi-constant curvature. We obtain Chen first inequality and a Chen inequality for the $delta (2,2)$-invariant for these manifolds.","PeriodicalId":43768,"journal":{"name":"International Electronic Journal of Geometry","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136134486","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 this study, our purpose is to determine the generalized rectifying-type curves with Frenet-type frame in Myller configuration for Euclidean 4-space $E_4$. Also, some characterizations of them are given. We construct some correlations between curvatures and invariants of generalized rectifying-type curves. Additionally, we obtain an illustrative example with respect to the rectifying-type curves with Frenet-type frame in Myller configuration for Euclidean 4-space $E_4$.
{"title":"A New Insight on Rectifying-Type Curves in Four-Dimensional Euclidean Space","authors":"Zehra İŞBİLİR, Murat TOSUN","doi":"10.36890/iejg.1291893","DOIUrl":"https://doi.org/10.36890/iejg.1291893","url":null,"abstract":"In this study, our purpose is to determine the generalized rectifying-type curves with Frenet-type frame in Myller configuration for Euclidean 4-space $E_4$. Also, some characterizations of them are given. We construct some correlations between curvatures and invariants of generalized rectifying-type curves. Additionally, we obtain an illustrative example with respect to the rectifying-type curves with Frenet-type frame in Myller configuration for Euclidean 4-space $E_4$.","PeriodicalId":43768,"journal":{"name":"International Electronic Journal of Geometry","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136133749","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}
Many techniques have been proposed to project the high-dimensional space into a low-dimensional space, one of the most famous methods being principal component analysis. The Klein quadric is a geometric shape defined by a second-degree homogeneous equation. The lines of projective three-space are, via the Klein mapping, in one-to-one correspondence with points of a hyperbolic quadric of the projective 5-space. This paper presents a research study on he images under the Klein mapping of the projectice 3-space order of 4 and the fuzzification of the Klein quadric in 5-dimensional projective space.
{"title":"Fuzzy Counterpart of Klein Quadric","authors":"Ziya AKÇA, Abdilkadir ALTINTAŞ","doi":"10.36890/iejg.1343784","DOIUrl":"https://doi.org/10.36890/iejg.1343784","url":null,"abstract":"Many techniques have been proposed to project the high-dimensional space into a low-dimensional space, one of the most famous methods being principal component analysis. The Klein quadric is a geometric shape defined by a second-degree homogeneous equation. The lines of projective three-space are, via the Klein mapping, in one-to-one correspondence with points of a hyperbolic quadric of the projective 5-space. This paper presents a research study on he images under the Klein mapping of the projectice 3-space order of 4 and the fuzzification of the Klein quadric in 5-dimensional projective space.","PeriodicalId":43768,"journal":{"name":"International Electronic Journal of Geometry","volume":"51 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136133511","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 this paper, we study Cotton solitons on three-dimensional almost α-paracosymplectic manifolds. We especially focus on threedimensional almost α-paracosymplectic manifolds with harmonic vector field ξ and characterize them for all possible types of operator h. Finally, we constructed an example which satisfies our results.
{"title":"COTTON SOLITONS ON THREE DIMENSIONAL ALMOST ALPHA-PARACOSYMPLECTIC MANIFOLDS","authors":"İrem KÜPELİ ERKEN, Mustafa ÖZKAN, Büşra SAVUR","doi":"10.36890/iejg.1316716","DOIUrl":"https://doi.org/10.36890/iejg.1316716","url":null,"abstract":"In this paper, we study Cotton solitons on three-dimensional almost α-paracosymplectic manifolds. We especially focus on threedimensional almost α-paracosymplectic manifolds with harmonic vector field ξ and characterize them for all possible types of operator h. Finally, we constructed an example which satisfies our results.","PeriodicalId":43768,"journal":{"name":"International Electronic Journal of Geometry","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136133745","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 this paper, almost product-like Riemannian manifolds are investigated. Basic properties on tangential hypersurfaces of almost product-like Riemannian manifolds are obtained. Some examples of tangential hypersurfaces are presented. Some relations involving the Riemannian curvature tensor of a tangential hypersurface are computed.
{"title":"Locally Product-like Statistical Manifolds and Their Hypersurfaces","authors":"Esra ERKAN, Kazuhiko TAKANO, Mehmet GÜLBAHAR","doi":"10.36890/iejg.1307467","DOIUrl":"https://doi.org/10.36890/iejg.1307467","url":null,"abstract":"In this paper, almost product-like Riemannian manifolds are investigated. Basic properties on tangential hypersurfaces of almost product-like Riemannian manifolds are obtained. Some examples of tangential hypersurfaces are presented. Some relations involving the Riemannian curvature tensor of a tangential hypersurface are computed.","PeriodicalId":43768,"journal":{"name":"International Electronic Journal of Geometry","volume":"46 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136133499","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 this paper, we study developable surfaces which are flat and normal approximation of parallel surfaces along curves associated with three special vector fields. It is known that a surface whose points are at a constant distance along the normal of the surface is called a parallel surface. We investigate singularities of such developable surfaces. We show that under what conditions the approach surfaces are parallel. Also, we show that the approach surfaces are constant angle ruled surfaces if the curves selected on the surfaces are isophote, relatively normal-slant helix and helix.
{"title":"Approximations of Parallel Surfaces Along Curves","authors":"Büşra KÖSE, Yusuf YAYLI","doi":"10.36890/iejg.1362590","DOIUrl":"https://doi.org/10.36890/iejg.1362590","url":null,"abstract":"In this paper, we study developable surfaces which are flat and normal approximation of parallel surfaces along curves associated with three special vector fields. It is known that a surface whose points are at a constant distance along the normal of the surface is called a parallel surface. We investigate singularities of such developable surfaces. We show that under what conditions the approach surfaces are parallel. Also, we show that the approach surfaces are constant angle ruled surfaces if the curves selected on the surfaces are isophote, relatively normal-slant helix and helix.","PeriodicalId":43768,"journal":{"name":"International Electronic Journal of Geometry","volume":"70 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136133578","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}
Using a new orthogonal frame with curvature in $E_1^3$ and we put forth a new general formulation for inextensible flows of space curves in this work. We demonstrate presufficient conditions and prove the necessary conditions for inextensible curve flow which is a partial differential equations (PDE) incorporating the curvatures and torsion.
{"title":"Inextensible flows of space curves according to a new orthogonal frame with curvature in E_1^3","authors":"Alperen KIZILAY, Atakan Tuğkan YAKUT","doi":"10.36890/iejg.1274663","DOIUrl":"https://doi.org/10.36890/iejg.1274663","url":null,"abstract":"Using a new orthogonal frame with curvature in $E_1^3$ and we put forth a new general formulation for inextensible flows of space curves in this work. We demonstrate presufficient conditions and prove the necessary conditions for inextensible curve flow which is a partial differential equations (PDE) incorporating the curvatures and torsion.","PeriodicalId":43768,"journal":{"name":"International Electronic Journal of Geometry","volume":"59 19","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136133633","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 that the property of being pointwise slant is transitive on a class of proper pointwise slant submanifolds of almost product Riemannian manifolds, and illustrate this fact with an example. For a given almost product Riemannian manifold $(M_1,g,varphi_1)$, we consider a sequence of pointwise slant submanifolds $(M_{i+1}hookrightarrow M_i)_{iin mathbb{N}^*}$, and we explicitly determine the relation between the slant functions. Moreover, we state this result in a more general case.
{"title":"On a Sequence of Slant Submanifolds in Almost Product Riemannian Setting","authors":"Adara M. BLAGA","doi":"10.36890/iejg.1321401","DOIUrl":"https://doi.org/10.36890/iejg.1321401","url":null,"abstract":"We prove that the property of being pointwise slant is transitive on a class of proper pointwise slant submanifolds of almost product Riemannian manifolds, and illustrate this fact with an example. For a given almost product Riemannian manifold $(M_1,g,varphi_1)$, we consider a sequence of pointwise slant submanifolds $(M_{i+1}hookrightarrow M_i)_{iin mathbb{N}^*}$, and we explicitly determine the relation between the slant functions. Moreover, we state this result in a more general case.","PeriodicalId":43768,"journal":{"name":"International Electronic Journal of Geometry","volume":"59 18","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136133634","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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