• Title/Summary/Keyword: Hypersurface

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A Study on the Characteristics of Digital Architecture Expressed in the Contemporary Fashion Works of Hussein Chalayan

  • Chun, Jae-Hoon
    • Journal of the Korean Society of Clothing and Textiles
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    • v.34 no.12
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    • pp.1957-1967
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    • 2010
  • This study analyses the qualities of digital architecture applying digital technologies by examining the qualities applied to the fashion designs of Husssein Chalayan. The aim of this study is to forecast in what ways the digital influence over fashion will evolve. This study was based on literature and case studies to examine the characteristics of digital architecture, and a case analysis of fashion design was conducted on the collections of Hussein Chalayan that draw heavily from technology. As a result, it was possible to classify the characteristics of digital architecture into five groups - immateriality, interactivity, nonlinearity, liquidity, and hypersurface; in addition, all of these characteristics were found in the works of Hussein Chalayan. The digital paradigm will continue to influence modern architecture and fashion in functional and/ or expressive terms that will continue to strengthen through the further advancement of digital technology.

ON SPECIAL CONFORMALLY FLAT SPACES WITH WARPED PRODUCT METRICS

  • Kim, Byung-Hak;Lee, Sang-Deok;Choi, Jin-Hyuk;Lee, Young-Ok
    • Journal of applied mathematics & informatics
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    • v.29 no.1_2
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    • pp.497-504
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    • 2011
  • In 1973, B. Y. Chen and K. Yano introduced the special conformally flat space for the generalization of a subprojective space. The typical example is a canal hypersurface of a Euclidean space. In this paper, we study the conditions for the base space B to be special conformally flat in the conharmonically flat warped product space $B^n{\times}_fR^1$. Moreover, we study the special conformally flat warped product space $B^n{\times}_fF^p$ and characterize the geometric structure of $B^n{\times}_fF^p$.

HORIZONTALLY HOMOTHETIC HARMONIC MORPHISMS AND STABILITY OF TOTALLY GEODESIC SUBMANIFOLDS

  • Yun, Gab-Jin;Choi, Gun-Don
    • Journal of the Korean Mathematical Society
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    • v.45 no.2
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    • pp.493-511
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    • 2008
  • In this article, we study the relations of horizontally homothetic harmonic morphisms with the stability of totally geodesic submanifolds. Let $\varphi:(M^n,g)\rightarrow(N^m,h)$ be a horizontally homothetic harmonic morphism from a Riemannian manifold into a Riemannian manifold of non-positive sectional curvature and let T be the tensor measuring minimality or totally geodesics of fibers of $\varphi$. We prove that if T is parallel and the horizontal distribution is integrable, then for any totally geodesic submanifold P in N, the inverse set, $\varphi^{-1}$(P), is volume-stable in M. In case that P is a totally geodesic hypersurface the condition on the curvature can be weakened to Ricci curvature.

MAXIMAL SPACE-LIKE HYPERSURFACES IN H14(-1) WITH ZERO GAUSS-KRONECKER CURVATURE

  • CHENG QING-MING;SUH YOUNG JIN
    • Journal of the Korean Mathematical Society
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    • v.43 no.1
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    • pp.147-157
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    • 2006
  • In this paper, we study complete maximal space-like hypersurfaces with constant Gauss-Kronecker curvature in an antide Sitter space $H_1^4(-1)$. It is proved that complete maximal spacelike hypersurfaces with constant Gauss-Kronecker curvature in an anti-de Sitter space $H_1^4(-1)$ are isometric to the hyperbolic cylinder $H^2(c1){\times}H^1(c2)$ with S = 3 or they satisfy $S{\leq}2$, where S denotes the squared norm of the second fundamental form.

ON THE STRUCTURE OF THE FUNDAMENTAL GROUP OF MANIFOLDS WITH POSITIVE SCALAR CURVATURE

  • Kim, Jin-Hong;Park, Han-Chul
    • Bulletin of the Korean Mathematical Society
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    • v.48 no.1
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    • pp.129-140
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    • 2011
  • The aim of this paper is to study the structure of the fundamental group of a closed oriented Riemannian manifold with positive scalar curvature. To be more precise, let M be a closed oriented Riemannian manifold of dimension n (4 $\leq$ n $\leq$ 7) with positive scalar curvature and non-trivial first Betti number, and let be $\alpha$ non-trivial codimension one homology class in $H_{n-1}$(M;$\mathbb{R}$). Then it is known as in [8] that there exists a closed embedded hypersurface $N_{\alpha}$ of M representing $\alpha$ of minimum volume, compared with all other closed hypersurfaces in the homology class. Our main result is to show that the fundamental group ${\pi}_1(N_{\alpha})$ is always virtually free. In particular, this gives rise to a new obstruction to the existence of a metric of positive scalar curvature.

ON BOUNDARY REGULARITY OF HOLOMORPHIC CORRESPONDENCES

  • Ourimi, Nabil
    • Journal of the Korean Mathematical Society
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    • v.49 no.1
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    • pp.17-30
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    • 2012
  • Let D be an arbitrary domain in $\mathbb{C}^n$, n > 1, and $M{\subset}{\partial}D$ be an open piece of the boundary. Suppose that M is connected and ${\partial}D$ is smooth real-analytic of finite type (in the sense of D'Angelo) in a neighborhood of $\bar{M}$. Let f : $D{\rightarrow}\mathbb{C}^n$ be a holomorphic correspondence such that the cluster set $cl_f$(M) is contained in a smooth closed real-algebraic hypersurface M' in $\mathbb{C}^n$ of finite type. It is shown that if f extends continuously to some open peace of M, then f extends as a holomorphic correspondence across M. As an application, we prove that any proper holomorphic correspondence from a bounded domain D in $\mathbb{C}^n$ with smooth real-analytic boundary onto a bounded domain D' in $\mathbb{C}^n$ with smooth real-algebraic boundary extends as a holomorphic correspondence to a neighborhood of $\bar{D}$.

COMPLEX SUBMANIFOLDS IN REAL HYPERSURFACES

  • Han, Chong-Kyu;Tomassini, Giuseppe
    • Journal of the Korean Mathematical Society
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    • v.47 no.5
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    • pp.1001-1015
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    • 2010
  • Let M be a $C^{\infty}$ real hypersurface in $\mathbb{C}^{n+1}$, $n\;{\geq}\;1$, locally given as the zero locus of a $C^{\infty}$ real valued function r that is defined on a neighborhood of the reference point $P\;{\in}\;M$. For each k = 1,..., n we present a necessary and sufficient condition for there to exist a complex manifold of dimension k through P that is contained in M, assuming the Levi form has rank n - k at P. The problem is to find an integral manifold of the real 1-form $i{\partial}r$ on M whose tangent bundle is invariant under the complex structure tensor J. We present generalized versions of the Frobenius theorem and make use of them to prove the existence of complex submanifolds.

SOBOLEV ESTIMATES FOR THE LOCAL EXTENSION OF BOUNDARY HOLOMORPHIC FORMS ON REAL HYPERSURFACES IN ℂn

  • Cho, Sanghyun
    • Journal of the Korean Mathematical Society
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    • v.50 no.3
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    • pp.479-491
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    • 2013
  • Let M be a smooth real hypersurface in complex space of dimension $n$, $n{\geq}3$, and assume that the Levi-form at $z_0$ on M has at least $(q+1)$-positive eigenvalues, $1{\leq}q{\leq}n-2$. We estimate solutions of the local $\bar{\partial}$-closed extension problem near $z_0$ for $(p,q)$-forms in Sobolev spaces. Using this result, we estimate the local solution of tangential Cauchy-Riemann equation near $z_0$ in Sobolev spaces.

PROJECTIONS OF ALGEBRAIC VARIETIES WITH ALMOST LINEAR PRESENTATION II

  • Ahn, Jeaman
    • Journal of the Chungcheong Mathematical Society
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    • v.34 no.2
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    • pp.181-188
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    • 2021
  • Let X be a nondegenerate reduced closed subscheme in ℙn. Assume that πq : X → Y = πq(X) ⊂ ℙn-1 is a generic projection from the center q ∈ Sec(X) \ X where Sec(X) = ℙn. Let Z be the singular locus of the projection πq(X) ⊂ ℙn-1. Suppose that IX has the almost minimal presentation, which is of the form R(-3)β2,1 ⊕ R(-4) → R(-2)β1,1 → IX → 0. In this paper, we prove the followings: (a) Z is either a linear space or a quadric hypersurface in a linear subspace; (b) $H^1({\mathcal{I}_X(k)})=H^1({\mathcal{I}_Y(k)})$ for all k ∈ ℤ; (c) reg(Y) ≤ max{reg(X), 4}; (d) Y is cut out by at most quartic hypersurfaces.

A NEW CLASSIFICATION OF REAL HYPERSURFACES WITH REEB PARALLEL STRUCTURE JACOBI OPERATOR IN THE COMPLEX QUADRIC

  • Lee, Hyunjin;Suh, Young Jin
    • Journal of the Korean Mathematical Society
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    • v.58 no.4
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    • pp.895-920
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    • 2021
  • In this paper, first we introduce the full expression of the Riemannian curvature tensor of a real hypersurface M in the complex quadric Qm from the equation of Gauss and some important formulas for the structure Jacobi operator Rξ and its derivatives ∇Rξ under the Levi-Civita connection ∇ of M. Next we give a complete classification of Hopf real hypersurfaces with Reeb parallel structure Jacobi operator, ∇ξRξ = 0, in the complex quadric Qm for m ≥ 3. In addition, we also consider a new notion of 𝒞-parallel structure Jacobi operator of M and give a nonexistence theorem for Hopf real hypersurfaces with 𝒞-parallel structure Jacobi operator in Qm, for m ≥ 3.