• 제목/요약/키워드: finite presentation

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A FINITE PRESENTATION FOR THE TWIST SUBGROUP OF THE MAPPING CLASS GROUP OF A NONORIENTABLE SURFACE

  • Stukow, Michal
    • 대한수학회보
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    • 제53권2호
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    • pp.601-614
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    • 2016
  • Let $N_{g,s}$ denote the nonorientable surface of genus g with s boundary components. Recently Paris and Szepietowski [12] obtained an explicit finite presentation for the mapping class group $\mathcal{M}(N_{g,s})$ of the surface $N_{g,s}$, where $s{\in}\{0,1\}$ and g + s > 3. Following this work, we obtain a finite presentation for the subgroup $\mathcal{T}(N_{g,s})$ of $\mathcal{M}(N_{g,s})$ generated by Dehn twists.

THEORY OF INFINITELY NEAR SINGULAR POINTS

  • Hironaka, Heisuke
    • 대한수학회지
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    • 제40권5호
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    • pp.901-920
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    • 2003
  • The notion of infinitely near singular points, classical in the case of plane curves, has been generalized to higher dimensions in my earlier articles ([5], [6], [7]). There, some basic techniques were developed, notably the three technical theorems which were Differentiation Theorem, Numerical Exponent Theorem and Ambient Reduction Theorem [7]. In this paper, using those results, we will prove the Finite Presentation Theorem, which the auther believes is the first of the most important milestones in the general theory of infinitely near singular points. The presentation is in terms of a finitely generated graded algebra which describes the total aggregate of the trees of infinitely near singular points. The totality is a priori very complex and intricate, including all possible successions of permissible blowing-ups toward the reduction of singularities. The theorem will be proven for singular data on an ambient algebraic shceme, regular and of finite type over any perfect field of any characteristics. Very interesting but not yet apparent connections are expected with many such works as ([1], [8]).

ON SOME FINITE SOLUBLE GROUPS WITH ZERO DEFICIENCY

  • Jamali, A.
    • 대한수학회보
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    • 제35권3호
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    • pp.465-471
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    • 1998
  • The class of finite solube groups with zero deficiency known to have soluble lenght five or six is small. In this paper we exhibit some classes of such goups.

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ON COMPLEX VARIABLE METHOD IN FINITE ELASTICITY

  • Akinola, Ade
    • Journal of applied mathematics & informatics
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    • 제12권1_2호
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    • pp.183-198
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    • 2003
  • We highlight the alternative presentation of the Cauchy-Riemann conditions for the analyticity of a complex variable function and consider plane equilibrium problem for an elastic transversely isotropic layer, in finite deformation. We state the fundamental problems and consider traction boundary value problem, as an example of fundamental problem-one. A simple solution of“Lame's problem”for an infinite layer is obtained. The profile of the deformed contour is given; and this depends on the order of the term used in the power series specification for the complex potential and on the material constants of the medium.

Sensitivity Analysis of the Galerkin Finite Element Method Neutron Diffusion Solver to the Shape of the Elements

  • Hosseini, Seyed Abolfazl
    • Nuclear Engineering and Technology
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    • 제49권1호
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    • pp.29-42
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    • 2017
  • The purpose of the present study is the presentation of the appropriate element and shape function in the solution of the neutron diffusion equation in two-dimensional (2D) geometries. To this end, the multigroup neutron diffusion equation is solved using the Galerkin finite element method in both rectangular and hexagonal reactor cores. The spatial discretization of the equation is performed using unstructured triangular and quadrilateral finite elements. Calculations are performed using both linear and quadratic approximations of shape function in the Galerkin finite element method, based on which results are compared. Using the power iteration method, the neutron flux distributions with the corresponding eigenvalue are obtained. The results are then validated against the valid results for IAEA-2D and BIBLIS-2D benchmark problems. To investigate the dependency of the results to the type and number of the elements, and shape function order, a sensitivity analysis of the calculations to the mentioned parameters is performed. It is shown that the triangular elements and second order of the shape function in each element give the best results in comparison to the other states.

객체지향개념을 이용한 유한요소 구조설계 시스템 개발 (Development of Finite Element Structural Design System using Object-Oriented Concept)

  • 이상갑;장승조
    • 해양환경안전학회지
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    • 제1권2호
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    • pp.83-94
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    • 1995
  • The purpose of this paper is to develop an integrated environment system for finite element structural analysis using OOA(Object-Oriented Analysis) and OOD(Object-Oriented Design), with may reduce inconveniencies in use such as file input of macro command and improve lacks of graphic presentation in the established finite element analysis program. This paper is attempted to suggest an easy approach to object-oriented concept and convenient programming. Two languages are used together in this paper instead of single C++ language for the development of object-oriented program. : Visual Basic with CDK(Custom Development Kit), and Borland C++ with OWL(Object Windows Library).

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Finite, Fiber-preserving Group Actions on Elliptic 3-manifolds

  • Peet, Benjamin
    • Kyungpook Mathematical Journal
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    • 제62권2호
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    • pp.363-388
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    • 2022
  • In two previous papers the author presented a general construction of finite, fiber- and orientation-preserving group actions on orientable Seifert manifolds. In this paper we restrict our attention to elliptic 3-manifolds. For illustration of our methods a constructive proof is given that orientation-reversing and fiber-preserving diffeomorphisms of Seifert manifolds do not exist for nonzero Euler class, in particular elliptic 3-manifolds. Each type of elliptic 3-manifold is then considered and the possible group actions that fit the given construction. This is shown to be all but a few cases that have been considered elsewhere. Finally, a presentation for the quotient space under such an action is constructed and a specific example is generated.

기둥(Post)과 핵(Core)의 이종재료 조합에 의한 치아의 유한요소해석 (A Finite Element Analysis of Incisors with Different Material Combinations of a Post and a Core)

  • 강민규;탁승민;이석순;서민석;김효진
    • 한국정밀공학회지
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    • 제28권4호
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    • pp.474-481
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    • 2011
  • The purpose of this study was to investigate the effect of rigidity of post core systems on stress distribution by the finite element stress analysis method. Three-dimensional finite element models simulating an endodontically treated maxillary central incisor restored with a zirconia crown were prepared. Each model contained cortical bone, trabecular bone, periodontal ligament, 4mm apical root canal filling, and post-and-core. A 50N static occlusal load was applied to the palatal surface of the crown with a $60^{\circ}$ angle to the long axis of the tooth. And three parallel type post (zirconia, glass fiber and stainless steel) and two core (Paracore and Tetric ceram) materials were evaluated, respectively. The differences in stress transfer characteristics of the models were analyzed. von Mises stresses were chosen for presentation of results and maximum displacement and hydrostatic pressure were also calculated. For the Result of the research, the model applied glass fiber to post material has lowest von Mises stress and it is suitable for material of post core systems.

AN EXAMPLE OF LARGE GROUPS

  • Cevik, Ahmet Sinan
    • 대한수학회보
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    • 제57권1호
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    • pp.195-206
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    • 2020
  • The fundamental idea of this article is to present an effective way to obtain the large groups in terms of the split extension obtained by a finite cyclic group and a free abelian group rank 2. The proof of the main result on largeness property of this specific split extension groups will be given by using the connection of large groups with the groups having deficiency one presentations.