We analyze composition methods with complex coefficients exhibiting the so-called “symmetry-conjugate” pattern in their distribution. In particular, we study behavior respect to preservation of qualitative properties when projected on real axis and compare them usual left-right palindromic compositions. New schemes within this family up order 8 are proposed efficiency is tested several examples...

A highly enantioselective copper-catalyzed conjugate addition of diethylzinc to acyclic aromatic enones was developed with phosphoramidite ligands bearing a D(2)-symmetric biphenyl backbone. This type of reaction demonstrated that toluene and THF solvents can completely reverse the absolute configuration of the products, thus simplifying the process of accessing either enantiomer (S: 92% ee, 94...

We consider the application of the conjugate gradient method to the solution of large, symmetric indefinite linear systems. Special emphasis is put on the use of constraint preconditioners and a new factorization that can reduce the number of flops required by the preconditioning step. Results concerning the eigenvalues of the preconditioned matrix and its minimum polynomial are given. Numerica...

Circulant preconditioners that cluster eigenvalues are well established for linear systems involving symmetric positive definite Toeplitz matrices. For these preconditioners rapid convergence of the preconditioned conjugate gradient method is guaranteed. Since circulant preconditioners can be applied quickly using the fast Fourier transform, preconditioned CG with circulant preconditioning is e...

Tbis paper describes a preconditioned conjugate gradient method tbat can be effectively implemented on both vector machines and parallel arrays to solve sparse symmetric and positive definite systema of linear equations. The implementation on the CYBER 203/205 and on tbe Finite Element Machine is discuased and result a obtained using the method on these machines are siven.

In this paper the conjugate gradient method, for solving fuzzy symmetric positive definite system of linear equation is considered. The method in detail is discussed and followed by convergence theorem and illustrated by solving some numerical examples. 2005 Elsevier Inc. All rights reserved.

We propose a solution to the problem of compatibility of Bose-Fermi statistics with symmetry transformations implemented by compact quantum groups of Drinfel’d type. We use unitary transformations to conjugate multiparticle symmetry postulates, so as to obtain a twisted realization of the symmetric groups Sn. *A. v. Humboldt-fellow e-mail: Fiore, Schupp @ ls-wess.physik.uni-muenchen.de

Let V be a vector space over a field F. The characteristic p of F is large if either p = 0 or p > dim V. When F is of large characteristic, the following questions, as well as their infinitesimal versions, are answered in this paper. Given an invertible linear map T : V → V, when does the vector space V admit a T -invariant non-degenerate symmetric (resp. skew-symmetric) biliner form? An elemen...

Previous single unit recordings and electrical stimulation have suggested that separate regions of the MRF participate in the control of vergence and conjugate eye movements. Neurons in the supraoculomotor area (SOA) have been found to encode symmetric vergence [Zhang, Y. et al. (1992). J. Neurophysiol., 67: 944-960] while neurons in the central MRF, the cMRF, located ventral to the SOA and lat...