• 제목/요약/키워드: a projective invariant

검색결과 37건 처리시간 0.023초

OPENLY SEMIPRIMITIVE PROJECTIVE MODULE

  • Bae, Soon-Sook
    • 대한수학회논문집
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    • 제19권4호
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    • pp.619-637
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    • 2004
  • In this paper, a left module over an associative ring with identity is defined to be openly semiprimitive (strongly semiprimitive, respectively) by the zero intersection of all maximal open fully invariant submodules (all maximal open submodules which are fully invariant, respectively) of it. For any projective module, the openly semiprimitivity of the projective module is an equivalent condition of the semiprimitivity of endomorphism ring of the projective module and the strongly semiprimitivity of the projective module is an equivalent condition of the endomorphism ring of the projective module being a sub direct product of a set of subdivisions of division rings.

ON A SEMI-INVARIANT SUBMANIFOLD OF CODIMENSION 3 WITH CONSTANT MEAN CURVATURE IN A COMPLEX PROJECTIVE SPACE

  • Lee, Seong-Baek
    • 대한수학회논문집
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    • 제18권1호
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    • pp.75-85
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    • 2003
  • Let M be 3 Semi-invariant submanifold of codimension 3 with lift-flat normal connection in a complex projective space. Further, if the mean curvature of M is constant, then we prove that M is a real hypersurface of a complex projective space of codimension 2 in the ambient space.

ON THE C-PROJECTIVE VECTOR FIELDS ON RANDERS SPACES

  • Rafie-Rad, Mehdi;Shirafkan, Azadeh
    • 대한수학회지
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    • 제57권4호
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    • pp.1005-1018
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    • 2020
  • A characterization of the C-projective vector fields on a Randers space is presented in terms of 𝚵-curvature. It is proved that the 𝚵-curvature is invariant for C-projective vector fields. The dimension of the algebra of the C-projective vector fields on an n-dimensional Randers space is at most n(n + 2). The generalized Funk metrics on the n-dimensional Euclidean unit ball 𝔹n(1) are shown to be explicit examples of the Randers metrics with a C-projective algebra of maximum dimension n(n+2). Then, it is also proved that an n-dimensional Randers space has a C-projective algebra of maximum dimension n(n + 2) if and only if it is locally Minkowskian or (up to re-scaling) locally isometric to the generalized Funk metric. A new projective invariant is also introduced.

AFFINE MANIFOLD WITH MEASURE PRESERVING PROJECTIVE HOLONOMY GROUP

  • Park, Yeong-Su
    • 대한수학회보
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    • 제38권1호
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    • pp.157-161
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    • 2001
  • In this paper, we prove that an affine manifold M is finitely covered by a manifold $\overline{M}$ where $\overline{M}$ is radiant or the tangent bundle of $\overline{M}$ has a conformally flat vector subbundle of the projective holonomy group of M admits an invariant probability Borel measure. This implies that$x^M$is zero.

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ON SOME SEMI-INVARIANT SUBMANIFOLDS OF CODIMENSION 3 IN A COMPLEX PROJECTIVE SPACE

  • Lee, Seong-Baek;Kim, Soo-Jin
    • 대한수학회논문집
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    • 제18권2호
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    • pp.309-323
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    • 2003
  • In this paper, We characterize a semi-invariant sub-manifold of codimension 3 satisfying ∇$\varepsilon$A = 0 in a complex projective space CP$\^$n+1/, where ∇$\varepsilon$A is the covariant derivative of the shape operator A in the direction of the distinguished normal with respect to the structure vector field $\varepsilon$.

SEMI-INVARIANT SUBMANIFOLDS OF CODIMENSION 3 OF A COMPLEX PROJECTIVE SPACE IN TERMS OF THE JACOBI OPERATOR

  • HER, JONG-IM;KI, U-HANG;LEE, SEONG-BAEK
    • 대한수학회보
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    • 제42권1호
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    • pp.93-119
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    • 2005
  • In this paper, we characterize some semi-invariant sub-manifolds of codimension 3 with almost contact metric structure ($\phi$, $\xi$, g) in a complex projective space $CP^{n+1}$ in terms of the structure tensor $\phi$, the Ricci tensor S and the Jacobi operator $R_\xi$ with respect to the structure vector $\xi$.

Improved image alignment algorithm based on projective invariant for aerial video stabilization

  • Yi, Meng;Guo, Bao-Long;Yan, Chun-Man
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제8권9호
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    • pp.3177-3195
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    • 2014
  • In many moving object detection problems of an aerial video, accurate and robust stabilization is of critical importance. In this paper, a novel accurate image alignment algorithm for aerial electronic image stabilization (EIS) is described. The feature points are first selected using optimal derivative filters based Harris detector, which can improve differentiation accuracy and obtain the precise coordinates of feature points. Then we choose the Delaunay Triangulation edges to find the matching pairs between feature points in overlapping images. The most "useful" matching points that belong to the background are used to find the global transformation parameters using the projective invariant. Finally, intentional motion of the camera is accumulated for correction by Sage-Husa adaptive filtering. Experiment results illustrate that the proposed algorithm is applied to the aerial captured video sequences with various dynamic scenes for performance demonstrations.

QUATERNIONICALLY PROJECTIVE CORRESPONDENCE ON AN ALMOST QUATERNIONIC STRUCTURE

  • Ki, U-Hang;Pak, Jin-Suk;Yoon, Dae-Won
    • 대한수학회지
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    • 제35권4호
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    • pp.855-867
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    • 1998
  • In the present paper, we introduce the notions of quaternionically planar curves and quaternionically projective transformations to the case of almost quaternionic manifold with symmetric affine connection. Also, we obtain an invariant tensor field under the quaternionically projective transformation, and show that a quaternionic Kahlerian manifold with such a vanishing tensor field is of constant Q-sectional curvature.

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