• Title/Summary/Keyword: operator equations

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Operator-splitting methods respecting eigenvalue problems for shallow shelf equations with basal drag

  • Geiser, Jurgen;Calov, Reinhard
    • Coupled systems mechanics
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    • v.1 no.4
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    • pp.325-343
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    • 2012
  • We present different numerical methods for solving the shallow shelf equations with basal drag (SSAB). An alternative approach of splitting the SSAB equation into a Laplacian and diagonal shift operator is discussed with respect to the underlying eigenvalue problem. First, we solve the equations using standard methods. Then, the coupled equations are decomposed into operators for membranes stresses, basal shear stress and driving stress. Applying reasonable parameter values, we demonstrate that the operator of the membrane stresses is much stiffer than the operator of the basal shear stress. Here, we could apply a new splitting method, which alternates between the iteration on the membrane-stress operator and the basal-shear operator, with a more frequent iteration on the operator of the membrane stresses. We show that this splitting accelerates and stabilize the computational performance of the numerical method, although an appropriate choice of the standard method used to solve for all operators in one step speeds up the scheme as well.

ITERATIVE ALGORITHMS FOR A SYSTEM OF RANDOM NONLINEAR EQUATIONS WITH FUZZY MAPPINGS

  • Kim, Jong Kyu;Salahuddin, Salahuddin
    • East Asian mathematical journal
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    • v.34 no.3
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    • pp.265-285
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    • 2018
  • The main purpose of this paper, by using the resolvent operator technique associated with randomly (A, ${\eta}$, m)-accretive operator is to establish an existence and convergence theorem for a class of system of random nonlinear equations with fuzzy mappings in Banach spaces. Our works are improvements and generalizations of the corresponding well-known results.

PROXIMAL POINTS METHODS FOR GENERALIZED IMPLICIT VARIATIONAL-LIKE INCLUSIONS IN BANACH SPACES

  • He, Xin-Feng;Lou, Jian;He, Zhen
    • East Asian mathematical journal
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    • v.28 no.1
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    • pp.37-47
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    • 2012
  • In this paper, we study generalized implicit variational-like inclusions and $J^{\eta}$-proximal operator equations in Banach spaces. It is established that generalized implicit variational-like inclusions in real Banach spaces are equivalent to fixed point problems. We also establish relationship between generalized implicit variational-like inclusions and $J^{\eta}$-proximal operator equations. This equivalence is used to suggest a iterative algorithm for solving $J^{\eta}$-proximal operator equations.

Remarks on volterra equations in Banach spaces

  • Kim, Mi-Hi
    • Communications of the Korean Mathematical Society
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    • v.12 no.4
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    • pp.1039-1064
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    • 1997
  • Existence and Uniqueness for Volterra equations (VE) with a weak regularity assumption on A, the relative closedness of A are investigaed by means of the Laplace transform theory. Also, (VE) are studied by means of the method of convoluted solution operator families.

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INEXACT-NEWTON METHOD FOR SOLVING OPERATOR EQUATIONS IN INFINITE-DIMENSIONAL SPACES

  • Liu Jing;Gao Yan
    • Journal of applied mathematics & informatics
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    • v.22 no.1_2
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    • pp.351-360
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    • 2006
  • In this paper, we develop an inexact-Newton method for solving nonsmooth operator equations in infinite-dimensional spaces. The linear convergence and superlinear convergence of inexact-Newton method under some conditions are shown. Then, we characterize the order of convergence in terms of the rate of convergence of the relative residuals. The present inexact-Newton method could be viewed as the extensions of previous ones with same convergent results in finite-dimensional spaces.

GENERALIZED JENSEN'S EQUATIONS IN A HILBERT MODULE

  • An, Jong Su;Lee, Jung Rye;Park, Choonkil
    • Korean Journal of Mathematics
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    • v.15 no.2
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    • pp.135-148
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    • 2007
  • We prove the stability of generalized Jensen's equations in a Hilbert module over a unital $C^*$-algebra. This is applied to show the stability of a projection, a unitary operator, a self-adjoint operator, a normal operator, and an invertible operator in a Hilbert module over a unital $C^*$-algebra.

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THE SOLUTIONS OF SOME OPERATOR EQUATIONS

  • Cvetkovic-Ilic, Dragana S.
    • Journal of the Korean Mathematical Society
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    • v.45 no.5
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    • pp.1417-1425
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    • 2008
  • In this paper we consider the solvability and describe the set of the solutions of the operator equations $AX+X^{*}C=B$ and $AXB+B^{*}X^{*}A^{*}=C$. This generalizes the results of D. S. Djordjevic [Explicit solution of the operator equation $A^{*}X+X^{*}$A=B, J. Comput. Appl. Math. 200(2007), 701-704].

A NOTE ON RADON-NIKODYM THEOREM FOR OPERATOR VALUED MEASURES AND ITS APPLICATIONS

  • Ahmed, Nasiruddin
    • Communications of the Korean Mathematical Society
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    • v.28 no.2
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    • pp.285-295
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    • 2013
  • In this note we present sufficient conditions for the existence of Radon-Nikodym derivatives (RND) of operator valued measures with respect to scalar measures. The RND is characterized by the Bochner integral in the strong operator topology of a strongly measurable operator valued function with respect to a nonnegative finite measure. Using this result we also obtain a characterization of compact sets in the space of operator valued measures. An extension of this result is also given using the theory of Pettis integral. These results have interesting applications in the study of evolution equations on Banach spaces driven by operator valued measures as structural controls.