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951.
Over an arbitrary ring of scalars, we build a Jordan algebra J having two elements x,y∈J such that x?y=0, but whose U-operators do not commute. This shows that nondegeneracy is a necessary condition in the main theorem of Commuting U-Operators in Jordan Algebras by J. A Anquela, T. Cortés and H. P. Petersson (Trans. Amer. Math. Soc. 366 (2014), 5877–5902). As a consequence, we obtain examples of Jordan systems over arbitrary rings of scalars that cannot be imbedded in nondegenerate systems. 相似文献
952.
Teresa?D’AprileEmail author Francesca?De?Marchis Isabella?Ianni 《Calculus of Variations and Partial Differential Equations》2018,57(4):99
We study the existence of at least one conformal metric of prescribed Gaussian curvature on a closed surface \(\Sigma \) admitting conical singularities of orders \(\alpha _i\)’s at points \(p_i\)’s. In particular, we are concerned with the case where the prescribed Gaussian curvature is sign-changing. Such a geometrical problem reduces to solving a singular Liouville equation. By employing a min–max scheme jointly with a finite dimensional reduction method, we deduce new perturbative results providing existence when the quantity \(\chi (\Sigma )+\sum _i \alpha _i\) approaches a positive even integer, where \(\chi (\Sigma )\) is the Euler characteristic of the surface \(\Sigma \). 相似文献
953.
Luz?M.?Fernández-CabreraEmail author Antón?Martínez 《Journal of Fourier Analysis and Applications》2018,24(5):1181-1203
We establish an analog for bilinear operators of the compactness interpolation result for bounded linear operators proved by Cwikel and Cobos, Kühn and Schonbek. We work with the assumption that \(T:(A_0+A_1) \times (B_0+B_1) \longrightarrow E_0+E_1\) is bounded, but we also study the case when this does not hold. Applications are given to compactness of convolution operators and compactness of commutators of bilinear Calderón–Zygmund operators. 相似文献
954.
Juan Bory Reyes Ricardo Abreu Blaya Martín P. Árciga Alejandre Yudier Peña Pérez 《Complex Analysis and Operator Theory》2018,12(5):1369-1382
In this paper we are interested in finding solvability conditions for Riemann and Dirichlet type boundary value problems with generalized Hölder-continuous boundary data in the case of hyperanalytic functions defined in a domain of the complex plane bounded by an h-summable closed curve. 相似文献
955.
Mijail Borges-Quintana Miguel Ángel Borges-Trenard Edgar Martínez-Moro 《Mathematics in Computer Science》2018,12(3):339-347
In this work we study a weak order ideal associated with the coset leaders of a non-binary linear code. This set allows the incrementally computation of the coset leaders and the definitions of the set of leader codewords. This set of codewords has some nice properties related to the monotonicity of the weight compatible order on the generalized support of a vector in \(\mathbb {F}_q^n\) which allows to describe a test set, a trial set and the set of zero neighbours of a linear code in terms of the leader codewords. 相似文献
956.
María Teresa Gallegos Gunter Ritter 《Advances in Data Analysis and Classification》2018,12(2):179-202
The present paper proposes a new strategy for probabilistic (often called model-based) clustering. It is well known that local maxima of mixture likelihoods can be used to partition an underlying data set. However, local maxima are rarely unique. Therefore, it remains to select the reasonable solutions, and in particular the desired one. Credible partitions are usually recognized by separation (and cohesion) of their clusters. We use here the p values provided by the classical tests of Wilks, Hotelling, and Behrens–Fisher to single out those solutions that are well separated by location. It has been shown that reasonable solutions to a clustering problem are related to Pareto points in a plot of scale balance vs. model fit of all local maxima. We briefly review this theory and propose as solutions all well-fitting Pareto points in the set of local maxima separated by location in the above sense. We also design a new iterative, parameter-free cutting plane algorithm for the multivariate Behrens–Fisher problem. 相似文献
957.
Bo Chen Fangyue Chen Junbiao Guan Genaro J. Mart ''{ i}nez 《Journal of Applied Analysis & Computation》2016,6(4):1164-1179
By introducing a sequence-block transformation and vector-block transformation, we explore the dynamical properties of hybrid cellular automation (HCA) and hybrid cellular automation with memory (HCAM) in the framework of symbolic dynamics. As the local evolution rules of HCA and HCAM are not-uniform, the new uniform cellular automata (CAs) with multiple states are constructed by specifical the block transformations. Furthermore, because the new CA rules are topologically conjugate with the originals, the complex dynamics of the HCA and HCAM rules can be investigated via the new CA rules. 相似文献
958.
J. H. Wang G. López V. Martín-Márquez C. Li 《Journal of Optimization Theory and Applications》2010,146(3):691-708
The relationship between monotonicity and accretivity on Riemannian manifolds is studied in this paper and both concepts are
proved to be equivalent in Hadamard manifolds. As a consequence an iterative method is obtained for approximating singularities
of Lipschitz continuous, strongly monotone mappings. We also establish the equivalence between the strong convexity of functions
and the strong monotonicity of its subdifferentials on Riemannian manifolds. These results are then applied to solve the minimization
of convex functions on Riemannian manifolds. 相似文献
959.
R. Andreani E. G. Birgin J. M. Martínez M. L. Schuverdt 《Computational Optimization and Applications》2010,45(2):209-236
A Nonlinear Programming algorithm that converges to second-order stationary points is introduced in this paper. The main tool
is a second-order negative-curvature method for box-constrained minimization of a certain class of functions that do not possess
continuous second derivatives. This method is used to define an Augmented Lagrangian algorithm of PHR (Powell-Hestenes-Rockafellar)
type. Convergence proofs under weak constraint qualifications are given. Numerical examples showing that the new method converges
to second-order stationary points in situations in which first-order methods fail are exhibited. 相似文献
960.
Koszul algebras have arisen in many contexts; algebraic geometry, combinatorics, Lie algebras, non-commutative geometry and
topology. The aim of this paper and several sequel papers is to show that for any finite dimensional algebra there is always
a naturally associated Koszul theory. To obtain this, the notions of Koszul algebras, linear modules and Koszul duality are
extended to additive (graded) categories over a field. The main focus of this paper is to provide these generalizations and
the necessary preliminaries. 相似文献