Let M be a simply connected complex submanifold of C . We prove that M is irreducible, up a totally geodesic factor, if and only if the normal holonomy group acts irreducibly. This is an extrinsic analogue of the well-known De Rham decomposition theorem for a complex manifold. Our result is not valid in the real context, as it is shown by many counter-examples.

In this study, the authors focus on quasi-hemi-slant submanifolds (qhs-submanifolds) of (α,β)-type almost contact manifolds, also known as trans-Sasakian manifolds. Essentially, we give sufficient and necessary conditions for integrability distributions using concept We consider geometry foliations dictated by distribution requirements manifolds with factors to be totally geodesic. Lastly, an i...

We show that any closed oriented immersed isotropic minimal surface Σ with genus gΣ in S ⊂ C is (1) Legendrian (and totally geodesic) if gΣ = 0; (2) either Legendrian or with exactly 2gΣ − 2 Legendrian points if gΣ ≥ 1. In general, any compact oriented immersed isotropic minimal submanifold L ⊂ S ⊂ C must be Legendrian if its first Betti number is zero. Corresponding results for nonorientable l...

In this article we investigate the geometry of CR-lightlike submanifolds in an indefinite Kähler product manifold. In particular, we obtain the necessary and sufficient conditions for a CR-lightlike submanifold in an indefinite Kähler product manifold to be either CR-lightlike product, or D-geodesic, or D′-geodesic. We also study totally umbilical and curvature-invariant CR-lightlike submanifol...

We obtain a basic inequality involving the Laplacian of the warping function and the squared mean curvature of any warped product isometrically immersed in a Riemannian manifold (cf. Theorem 2.2). Applying this general theory, we obtain basic inequalities involving the Laplacian of the warping function and the squared mean curvature of C-totally real warped product submanifolds of (κ, μ)-space ...

Moduli spaces of holomorphic disks in a complex manifold Z, with boundaries constrained to lie in a maximal totally real submanifold P , have recently been found to underlie a number of geometrically rich twistor correspondences. The purpose of this paper is to develop a general Fredholm regularity criterion for holomorphic curves-withboundary (Σ, ∂Σ) ⊂ (Z,P ), and then show how this applies, i...

Given a connected, compact, totally geodesic submanifold Ym of noncompact type inside a compact locally symmetric space of noncompact type Xn , we provide a sufficient condition that ensures that [Ym] 6= 0 ∈ Hm(X; R); in low dimensions, our condition is also necessary. We provide conditions under which there exist a tangential map of pairs from a finite cover (X̄, Ȳ) to the nonnegatively curved ...

In this paper we study n-dimensional compact minimal submanifolds in S with scalar curvature S satisfying the pinching condition S > n(n − 2). We show that for p ≤ 2 these submanifolds are totally geodesic (cf. Theorem 3.2 and Corollary 3.1). However, for codimension p ≥ 2, we prove the result under an additional restrictions on the curvature tensor corresponding to the normal connection (cf. T...

Let X be the matrix unit ball in Mn−k,k(K) consisting of contractive matrices where K = R, C, H. The domain X is a realization of the symmetric space G/K with G = U(n− k, k; K). The matrix ball yo of lower dimension in Mk′−k,k with k ′ ≤ n is a totally geodesic submanifold of X and let Y be the manifold of all G-translations of the submanifold y0. We consider the Radon transform from functions ...

This article concerned on the study of signature submanifolds for curves under Lie group actions SE(2), SA(2) and for surfaces under SE(3). Signature submanifold is a regular submanifold which its coordinate components are differential invariants of an associated manifold under Lie group action, and therefore signature submanifold is a key for solving equivalence problems.