Differential Geometry of Submanifolds in Complex Space Forms Involving δ-Invariants

Abstract

One of the fundamental problems in the theory of submanifolds is to establish optimal relationships between intrinsic and extrinsic invariants for submanifolds. In order to establish such relations, the first author introduced in the 1990s the notion of δ-invariants for Riemannian manifolds, which are different in nature from the classical curvature invariants. The earlier results on δ-invariants and their applications have been summarized in the first author’s book published in 2011 Pseudo-Riemannian Geometry, δ-Invariants and Applications (ISBN: 978-981-4329-63-7). In this survey, we present a comprehensive account of the development of the differential geometry of submanifolds in complex space forms involving the δ-invariants done mostly after the publication of the book.

On isometric immersions of almost $k$-product manifolds

“…Remark 1. The δmix -invariants are related with B.-Y Chen's δ-invariants, e.g., [5]. Indeed, if k ≥ 2 and the sectional curvature K ≥ 0, then δmix (n 1 , .…”

“…, D k ), see [14]. Our inequality also contains mixed scalar curvature type invariants related to B.-Y Chen's δ-invariants for k ≥ 2, for example, [4,5].…”

“…Multiply warped products have been studied from extrinsic geometry point of view in a series of articles, see [4,5] for an overview. B.Y.…”

Casorati Inequalities for Statistical Submanifolds in Kenmotsu Statistical Manifolds of Constant ϕ-Sectional Curvature with Semi-Symmetric Metric Connection

“…The study of simple relationships between the main intrinsic and extrinsic invariants of submanifolds is a fundamental problem in submanifold theory [ 1 ]. Recent research shows a growing trend in approaching this fascinating problem through an approach that proves some types of geometric inequalities (see, e.g., [ 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 ]).…”

“…The topic of -Casorati curvatures will appeal to more geometers focused on finding new solutions of the above problem. In this respect, some recent developments are devoted to inequalities on various submanifolds of a statistical manifold , notion defined by Amari [ 18 ] in 1985 in the realm of information geometry [ 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 ]. In this setting, the Fisher information metric is one of the most important metrics that can be considered on statistical models [ 19 ].…”