Descripción: Let k be a field, A a finite-dimensional Frobenius k-algebra and ρ: A → A, the Nakayama automorphism of A with respect to a Frobenius homomorphism φ: A → k. Assume that k has finite order m and that k has a primitive m-th root of unity w. Consider the decomposition A = A0 ⊕ ... ⊕ Am-1 of A, obtained by defining Ai = {a ∈ A : ρ(a) = wia}, and the decomposition HH*(A) = ⊕i=0 m-1 HHi* Hochschild cohomology of A, obtained from the decomposition of A. In this paper we prove that HH*(A) = HH0*(A) and that if the decomposition of A is strongly ℤ/mℤ-graded, then ℤ/mℤ acts on HH*(A 0) and HH*(A) = HH0*(A) = HH*(A 0)ℤ/mℤ.

Descripción: We study the existence of atomic decompositions for tensor products of Banach spaces and spaces of homogeneous polynomials. If a Banach space X admits an atomic decomposition of a certain kind, we show that the symmetrized tensor product of the elements of the atomic decomposition provides an atomic decomposition for the symmetric tensor product ⊗s, μ n X, for any symmetric tensor norm μ. In addition, the reciprocal statement is investigated and analogous consequences for the full tensor product are obtained. Finally we apply the previous results to establish the existence of monomial atomic decompositions for certain ideals of polynomials on X. © 2008 Elsevier Inc. All rights reserved.

Descripción: This work describes a simple spatial decomposition of the first-order reduced density matrix corresponding to an N -electron system into first-order density matrices, each of them associated to an atomic domain defined in the theory of atoms in molecules. A study of the representability of the density matrices arisen from this decomposition is reported and analyzed. An appropriate treatment of the eigenvectors of the matrices defined over atomic domains or over unions of these domains allows one to describe satisfactorily molecular properties and chemical bondings within a determined molecule and among its fragments. Numerical determinations, performed in selected molecules, confirm the reliability of our proposal. © 2005 American Institute of Physics.

Descripción: There is a Chern character from K-theory to negative cyclic homology. We show that it preserves the decomposition coming from Adams operations, at least in characteristic zero. © 2009 Springer-Verlag.

Descripción: Every finite dimensional Hopf algebra is a Frobenius algebra, with Frobenius homomorphism given by an integral. The Nakayama automorphism determined by it yields a decomposition with degrees in a cyclic group. For a family of pointed Hopf algebras, we determine necessary and sufficient conditions for this decomposition to be strongly graded. © 2006 Elsevier Ltd. All rights reserved.

Descripción: In this article we construct affine systems that provide a simultaneous atomic decomposition for a wide class of functional spaces including the Lebesgue spaces Lp(Rd), 1 < p < + ∞. The novelty and difficulty of this construction is that we allow for non-lattice translations.We prove that for an arbitrary expansive matrix A and any set Λ-satisfying a certain spreadness condition but otherwise irregular-there exists a smooth window whose translations along the elements of Λ and dilations by powers of A provide an atomic decomposition for the whole range of the anisotropic Triebel-Lizorkin spaces. The generating window can be either chosen to be bandlimited or to have compact support.To derive these results we start with a known general "painless" construction that has recently appeared in the literature. We show that this construction extends to Besov and Triebel-Lizorkin spaces by providing adequate dual systems. © 2012 Elsevier Ltd.

Descripción: We examine the decomposition of forced Taylor-Green and Arn'old-Beltrami-Childress (ABC) flows into coherent and incoherent components using an orthonormal wavelet decomposition. We ask whether wavelet coefficient thresholding based on the Donoho-Johnstone criterion can extract a coherent vortex signal while leaving behind Gaussian random noise. We find that no threshold yields a strictly Gaussian incoherent component, and that the most Gaussian incoherent flow is found for data compression lower than that achieved with the fully iterated Donoho-Johnstone threshold. Moreover, even at such low compression, the incoherent component shows clear signs of large-scale spatial correlations that are signatures of the forcings used to drive the flows. © 2012 American Institute of Physics.

Descripción: In this paper we generalize an interpolation result due to J.-O. Strömberg and A. Torchinsky to the case of one-sided Hardy spaces. This generalization is important in the study of the weak type (1,1) for lateral strongly singular operators. We shall need an atomic decomposition in which for every atom there exists another atom supported contiguously at its right. In order to obtain this decomposition we have developed a rather simple technique to break up an atom into a sum of others atoms. © 2006 by Institut Mittag-Leffler. All rights reserved.

Descripción: In this paper we present a probabilistic algorithm which computes, from a finite set of polynomials defining an algebraic variety V, the decomposition of V into equidimensional components. If V is defined by s polynomials in n variables of degrees bounded by an integer d ≥ n and V = ∪l=0 r Vℓ is the equidimensional decomposition of V, the algorithm obtains in sequential time bounded by sO(1)dO(n), for each 0 ≤ ℓ ≤r, a set of n + 1 polynomials of degrees bounded by deg(Vℓ) which define Vℓ. © 2002 Elsevier Science B.V. All rights reserved.

Descripción: This work describes simple decompositions of the energy of molecular systems according to schemes that partition the three-dimensional space. The components of those decompositions depend on one and two atomic domains thus providing a meaningful chemical information about the nature of different bondings among the atoms which compose the system. Our algorithms can be applied at any level of theory (correlated or uncorrelated wave functions). The results reported here, obtained at the Hartree-Fock level in selected molecules, show a good agreement with the chemical picture of molecules and require a low computational cost in comparison with other previously reported decompositions.

Descripción: The factorization theorems are a generalization for J-biexpansive meromorphic operator-valued functions on an infinite-dimensional Hilbert space of the theorems on decomposition of J-expansive matrix functions on a finite-dimensional Hilbert space due to A. V. Efimov and V. P. Potapov [Uspekhi Mat. Nauk 28 (1973), 65-130; Trudy Moskov. Mat. Obšč. 4 (1955), 125-236]. They also generalize theorems on factorization of J-expansive meromorphic operator functions due to Ju. P. Ginzburg [Izv. Vysš. Učebn. Zaved. Matematika 32 (1963), 45-53]. Within the framework of generalized network theory, the results can be applied to the J-biexpansive real operators that characterize a Hilbert port. Application of the extraction procedure to a given real operator leads to its splitting into a product of real factors, corresponding to Hilbert ports of a simpler structure. This can be interpreted as an extension of the classical method of synthesis of passive n-ports by factor decomposition. © 1981.

Descripción: We present a new technique suitable for a detailed comparison between solar dynamo models and observations. The method is based on the technique of dynamo spectroscopy proposed by Hoyng & Schutgens (1995) and bi-orthogonal decomposition of solar data. This decomposition provides a representation of the mean and fluctuating components of the flows, yielding relevant information for the comparison. To illustrate the method, we use a simple kinematic dynamo model of the solar cycle. Irregularities are introduced in the evolution of the magnetic fields modeling the turbulent behavior of the solar convective region with a random perturbation on the external source for the poloidal field. After fine tuning the parameters of the model we obtain solar like solutions displaying a magnetic cycle of 22 years, with fluctuations in its period and amplitude. In addition, the model generates Maunder-like events with a time span of 60-100 years.

Descripción: Factorization of J-biexpansive operator-valued functions on an infinite-dimensional Hilbert space is performed, to extract terms with an arbitrary number of poles of first order on the left and right half planes. Special emphasis is given to the case of reciprocal poles, which has an application to the synthesis of reciprocal passive linear systems as an extension of the classical synthesis of reciprocal n-ports by factor decomposition. © 1986.

Descripción: A factorization method is given to extract poles located on the imaginary axis for J-biexpansive meromorphic operator-valued functions acting on an infinite-dimensional Hilbert space. Decomposition of a real operator in terms of real factors, applicable to Hilbert ports, is also described, thus generalizing synthesis techniques originally developed for passive n-ports. © 1985.

Descripción: The effective action for quantum fields on a d-dimensional spacetime can be computed using a non-local expansion in powers of the curvature. We show explicitly that, for conformal fields and up to quadratic order in the curvature, the non-local effective action is equivalent to the d + 1 action for classical gravity in AdSd+1 restricted to a (d - 1)-brane. This generalizes previous results about quantum corrections to the Newtonian potential and provides an alternative method for making local a non-local effective action. The equivalence can be easily understood by comparing the Kallen-Lehmann decomposition of the classical propagator with the spectral representation of the non-local form factors in the quantum effective action. © 2001 Published by Elsevier Science B.V.

Descripción: A procedure for the construction of balanced orthogonal nonseparable quincunx multiwavelets, having filters with good lowpass properties, is introduced. The matrix filter bank is viewed as the polyphase matrix of other filters, upon which the lowpass condition is imposed. The multiscaling functions obtained are plotted by means of the cascade algorithm. The process of transforming an image with these wavelets is outlined: formulae for analysis and synthesis are given, the first steps are illustrated with images, and the decomposition of the original image into two input images is addressed. Compression is achieved in a nonlinear process. Experimental results show that (i) the constructed multiwavelets having lowpass properties perform better than other nonseparable multiwavelets, (ii) the energy compaction in the fine detail subbands is greater for the multiwavelets than for the one-dimensional wavelets tried.

Descripción: A theoretical study of the relation between the relativistic formulation of the nuclear magnetic shielding and spin-rotation tensors is presented. To this end a theoretical expression of the relativistic spin-rotation tensor is formulated, considering a molecular Hamiltonian of relativistic electrons and non-relativistic nuclei. Molecular rotation effects are introduced considering the terms of the Born-Oppenheimer decomposition, which couple the electrons and nuclei dynamics. The loss of the simple relation linking both spectral parameters in the non-relativistic formulation is further analyzed carrying out a perturbative expansion of relativistic effects by means of the linear response within the elimination of the small component approach. It is concluded that relativistic effects on the spin-rotation tensor are less important than those of the nuclear magnetic shielding tensor. © 2012 American Institute of Physics.

Descripción: A simple model based on the Hasegawa-Mima equation is used to study dipole vortex interactions and turbulence of electrostatic drift waves in a plasma. It is shown that if nonlinear effects are important during vortex collisions, dipoles are broken into monopoles. Nonadiabatic effects also affect dipole behavior, which can be destroyed by the instability of emitted waves (dipole vortex radiation). Simulations of turbulence in both decaying and driven cases show the appearance of long-lived monopole structures. These coherent structures contribute to stop the cascade of energy to large scales, and then to reach a self-organized stationary state. Some numerical evidence is done that Hasegawa-Mima turbulence has a long-time behavior that is much richer than the thermodynamic equilibrium state observed in two-dimensional hydrodynamics. In driven turbulence, an important departure from Gaussian statistics of vorticity fluctuations is found, giving some indication of intermittency. Using various analyzing techniques, in particular the proper orthogonal decomposition, we show that the turbulence can be characterized by a field of coherent structures, which dominates the dynamics of the system, and random waves interacting weakly with the coherent structures. (c) 1995 The American Physical Society © 1995 The American Physical Society.