• The Pure and Applied Mathematics
• /
• v.18 no.4
• /
• pp.353-359
• /
• 2011

In this paper, we characterize a semi-Riemannian manifolds satisfies the axiom of indefinite surfaces. We obtain the following result: If a semi-Riemannian manifold satisfies the axiom of indefinite surfaces, then it is a real space form.

• Bulletin of the Korean Mathematical Society
• /
• v.31 no.1
• /
• pp.25-33
• /
• 1994

In [2] we proved that if the minimum of the sectional curvature of a compact real minimal hypersurface of CP$^{m}$ is 1/(2m-1), then M is the geodesic hypersphere. This result was generalized in [8] to the case of M is a generic submanifold with flat normal connection. The purpose of the present paper is to prove a following generalization of theorems in [2] and [8].

• Kyungpook Mathematical Journal
• /
• v.56 no.1
• /
• pp.273-293
• /
• 2016

In this paper, we obtain that every biharmonic non-degenerate hypersurfaces in semi-Euclidean space $E^5_s$ with constant scalar curvature of diagonal shape operator has zero mean curvature.

• Kyungpook Mathematical Journal
• /
• v.48 no.1
• /
• pp.109-121
• /
• 2008

We determine maximal space-like hypersurfaces which are the images of subbundles of the normal bundle of m-dimensional totally geodesic space-like submanifolds of an (m + 2)-dimensional Lorentzian space form $\tilde{M}_1^{m+2}$(c) under the normal exponential map. Then we construct examples of maximal space-like hypersurfaces of $\tilde{M}_1^{m+2}$(c).

• The Pure and Applied Mathematics
• /
• v.17 no.1
• /
• pp.51-63
• /
• 2010

In this paper, we prove two characterization theorems for real half lightlike submanifold (M,g,S(TM)) of an indefinite Kaehler manifold $\bar{M}$ or an indefinite complex space form $\bar{M}$(c) subject to the conditions : (a) M is totally umbilical in $\bar{M}$, or (b) its screen distribution S(TM) is totally umbilical in M.

• The Pure and Applied Mathematics
• /
• v.17 no.1
• /
• pp.29-38
• /
• 2010

We study the geometry of half light like submanifold M of a semi-Riemannian space form $\bar{M}$(c) subject to the conditions : (a) the screen distribution on M is totally umbilic in M and the coscreen distribution on M is conformal Killing on $\bar{M}$ or (b) the screen distribution is totally geodesic in M and M is irrotational.

• Journal of the Chungcheong Mathematical Society
• /
• v.24 no.4
• /
• pp.769-781
• /
• 2011

We study the geometry of half lightlike sbmanifolds M of a semi-Riemannian space form $\tilde{M}(c)$ admitting a semi-symmetric metric connection subject to the conditions: (1) The screen distribution S(TM) is totally umbilical (geodesic) and (2) the co-screen distribution $S(TM^{\bot})$ of M is a conformal Killing one.

• Honam Mathematical Journal
• /
• v.43 no.4
• /
• pp.655-665
• /
• 2021

In the present paper, we study the geometric properties of the invariant submanifold of an almost Kenmotsu structure whose Riemannian curvature tensor has (𝜅, 𝜇, 𝜈)-nullity distribution. In this connection, the necessary and sufficient conditions are investigated for an invariant submanifold of an almost Kenmotsu (𝜅, 𝜇, 𝜈)-space to be totally geodesic under the behavior of functions 𝜅, 𝜇, and 𝜈.

• Honam Mathematical Journal
• /
• v.45 no.1
• /
• pp.25-41
• /
• 2023

In this paper, we study doubly warped product point-wise bi-slant submanfolds of S-space form. Here we try to establish an inequality containing the Ricci curvature, squared norm of mean curvature and the warping function.

• Journal of the Korean Mathematical Society
• /
• v.60 no.5
• /
• pp.1109-1133
• /
• 2023

We prove that the two-step flag variety 𝓕ℓ(1, n; n+1) carries a non-displaceable and non-monotone Lagrangian Gelfand-Zeitlin fiber diffeomorphic to S³ × T^2n-4 and a continuum family of non-displaceable Lagrangian Gelfand-Zeitlin torus fibers when n > 2.