Journal•ISSN: 0047-2468
Journal of Geometry
About: Journal of Geometry is an academic journal. The journal publishes majorly in the area(s): Projective plane & Projective space. It has an ISSN identifier of 0047-2468. Over the lifetime, 2051 publication(s) have been published receiving 12320 citation(s).
Topics: Projective plane, Projective space, Collineation, Affine transformation, Duality (projective geometry)
Papers published on a yearly basis
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TL;DR: S-functions are mappings from the class of finite graphs into the set of integers, such that certain formal conditions are fulfilled which are shared by the chromatic number, the vertex-connectivity, and the homomorphism-degree as discussed by the authors.
Abstract: S-functions are mappings from the class of finite graphs into the set of integers, such that certain formal conditions are fulfilled which are shared by the chromatic number, the vertex-connectivity, and the homomorphism-degree. The S-functions form a complete lattice (with respect to their natural partial order). The classes of graphs with values
250 citations
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TL;DR: In this paper, the necessary and sufficient conditions for the Mannheim partner curves in Euclidean space and Minkowski space were obtained for three-dimensional space, respectively, and some examples are also given.
Abstract: In this paper, we study Mannheim partner curves in three dimensional space. We obtain the necessary and sufficient conditions for the Mannheim partner curves in Euclidean space $${\mathbb{E}}^{3}$$
and Minkowski space $${\mathbb{E}}^{3}_{1}$$
, respectively. Some examples are also given.
138 citations
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TL;DR: In this article, Boyer and Galicki showed that a complete K-contact gradient soliton is a Jacobi vector field along the geodesics of the Reeb vector field.
Abstract: Inspired by a result of Boyer and Galicki, we prove that a complete K-contact gradient soliton is compact Einstein and Sasakian. For the non-gradient case we show that the soliton vector field is a Jacobi vector field along the geodesics of the Reeb vector field. Next we show that among all complete and simply connected K-contact manifolds only the unit sphere admits a non-Killing holomorphically planar conformal vector field (HPCV). Finally we show that, if a (k, μ)-contact manifold admits a non-zero HPCV, then it is either Sasakian or locally isometric to E3 or En+1 × Sn (4).
116 citations
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TL;DR: A subset of a (cristallographical) lattice ℒn is called convex whenever it is the intersection of the lattice with a convex set of the affine space containing ℓ n as discussed by the authors.
Abstract: A subset of a (cristallographical) lattice ℒn is called convex whenever it is the intersection of the lattice with a convex set of the affine space containing ℒn. We give a characterization of the convex sets which is intrinsic to the lattice and do the same for other related notions, e.g. the boundary of a convex set of ℒn. A statement analogous to Helly's theorem is also proved.
106 citations
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TL;DR: In this paper, the authors characterize almost contact metric manifolds which are CR-integrable almost Kenmotsu, through the existence of a suitable linear connection, and give examples and completely describe the three dimensional case.
Abstract: We characterize almost contact metric manifolds which are CR-integrable almost Kenmotsu, through the existence of a suitable linear connection. We classify almost Kenmotsu manifolds satisfying a certain nullity condition, we give examples and completely describe the three dimensional case.
97 citations