Papers by Dr. Punam Gupta
The purpose of the present paper is to introduce the conformal semi-invariant ξ ^⊥-Riemannian sub... more The purpose of the present paper is to introduce the conformal semi-invariant ξ ^⊥-Riemannian submersions from almost contact metric manifolds onto Riemannian manifolds as a generalization of anti-invariant submersions, semi-invariant submersions, anti-invariant ξ ^⊥-submersions, semi-invariant ξ ^⊥ ^⊥-submersions, conformal semi-invariant submersions. We obtain characterizations and investigate the integrability of distributions which are arisen from the definition of conformal semi-invariantξ^⊥-Riemannian submersions. We find out the necessary and sufficient conditions for a conformal semi-invariantξ^⊥-Riemannian submersions to be totally geodesic and harmonic. Finally, examples are also given for conformal semi-invariant submersions with horizontal Reeb vector field.
Vector bundles satisfying the point property
Journal of Algebra and Its Applications
In this note, we prove that vector bundles which satisfy the point property over a very general p... more In this note, we prove that vector bundles which satisfy the point property over a very general principally polarized Jacobian, Prym and abelian variety are indecomposable. We also compare two known constructions of vector bundles satisfying the point property over a very general principally polarized abelian surface.
Journal of Mathematics
A tiling of the Euclidean plane, by regular polygons, is called 2-uniform tiling if it has two or... more A tiling of the Euclidean plane, by regular polygons, is called 2-uniform tiling if it has two orbits of vertices under the action of its symmetry group. There are 20 distinct 2-uniform tilings of the plane. Plane being the universal cover of torus and Klein bottle, it is natural to ask about the exploration of maps on these two surfaces corresponding to the 2-uniform tilings. We call such maps as doubly semiequivelar maps. In the present study, we compute and classify (up to isomorphism) doubly semiequivelar maps on torus and Klein bottle. This classification of semiequivelar maps is useful in classifying a category of symmetrical maps which have two orbits of vertices, named as 2-uniform maps.
Tamkang Journal of Mathematics
In this paper, the non-existence of connected, compact Einstein doubly warped product semi-Rieman... more In this paper, the non-existence of connected, compact Einstein doubly warped product semi-Riemannian manifold with non-positive scalar curvature is proved. It is also shown that there does not exist non-trivial connected Einstein doubly warped product semi-Riemannian manifold with compact base $B$ or fibre $F$.
On $3$-dimensional $ left( varepsilon right)$-para Sasakian manifold
(N(k), ξ)-semi-Riemannian manifolds are defined. Examples and properties of (N(k), ξ)-semi-Rieman... more (N(k), ξ)-semi-Riemannian manifolds are defined. Examples and properties of (N(k), ξ)-semi-Riemannian manifolds are given. Some basic relations involving Ta-curvature tensor in (N(k), ξ)-semi-Riemannian manifolds are proved. It is proved that if M is an n-dimensional ξ-Ta-flat (N(k), ξ)-semi-Riemannian manifold, then it is η-Einstein under an algebraic condition. It is also proved that a semi-Riemannian manifold, which is T-recurrent or Tsymmetric, is always T-semisymmetric, where T is any tensor of type (1, 3). (Ta, Tb)-semisymmetric semi-Riemannian manifold is defined and studied. Several interesting results for Ta-semisymmetric, Ta-symmetric and Ta-recurrent (N(k), ξ)-semi-Riemannian manifolds are obtained. The definition of (Ta, STb )-semisymmetric semi-Riemannian manifold is given. (Ta, STb)-semisymmetric (N(k), ξ)-semi-Riemannian manifolds are classified. Some results for Ta-Riccisemisymmetric (N(k), ξ)-semi-Riemannian manifolds are obtained.
Definition of $({\cal T}_{a},{\cal T}_{b})$-pseudosymmetric semi-Riemannian manifold is given. $(... more Definition of $({\cal T}_{a},{\cal T}_{b})$-pseudosymmetric semi-Riemannian manifold is given. $({\cal T}_{a},{\cal T}_{b})$-pseudosy mmetric $(N(k),\xi)$-semi-Riemannian manifolds are classified. Some results for ${\cal T}_{a}$-pseudosymmetric $(N(k),\xi)$-semi-Riemannian manifolds are obtained. $({\cal T}_{a},{\cal T}_{b},S^{\ell})$-pseudosymmetric semi-Riemannian manifolds are defined. $({\cal T}_{a},{\cal T}_{b},S^{\ell})$-pseudosymmetric $(N(k),\xi)$-semi-Riemannian manifolds are classified. Some results for $(R,{\cal T}_{a},S^{\ell})$-pseudosymmetric $(N(k),\xi)$-semi-Riemannian manifolds are obtained. In particular, some results for $(R,{\cal T}_{a},S)$-pseudosymmetric $(N(k),\xi)$-semi-Riemannian manifolds are also obtained. After that, the definition of $({\cal T}_{a},S_{{\cal T}_{b}})$-pseudosymmetric semi-Riemannian manifold is given. $({\cal T}_{a},S_{{\cal T}_{b}})$-pseudosymmetric $(N(k),\xi)$-semi-Riemannian manifolds are classified. It is proved that a $(R,S_{{\cal T...
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Papers by Dr. Punam Gupta