Madness and weak forms of normality

Acta Mathematica Hungarica - We consider weakenings of normality in $$\Psi$$ -spaces and prove that the existence of an AD family whose $$\Psi$$ -space is almost-normal but not normal follows from...     

On the asymptotic normality of sequences of weak dependent random variables

The aim of this paper is to investigate the asymptotic normality for strong mixing sequences of random variables in the absense of stationarity or strong mixing rates. An additional condition is imposed to the coefficients of interlaced mixing. The results are applied to linear processes of strongly mixing sequences. The class of applications include filters of certain Gaussian sequences.Supported in part by an NSF grant, cost-sharing from the University of Cincinnati, and a Taft research grant.     

On a weak form of equational compactness

In this paper, we discuss a property of large systems of equations over universal algebras which does not appear to be generally known, but which coincides with equational compactness for abelian groups. It is shown, for example, that if is a cardinal number with uncountable cofinality, then every finitely solvable system of equations over any countable algebra has a solvable subsystem consisting also of equations. As an application, this property is used to generalize some results of Jensen and Lenzing on the non-compactness of ultrapowers of modules. Received November 11, 1997; accepted in final form March 2, 1998.     

A weak form of interpolation in equational logic

The notions of a weak interpolation property and of weak amalgamation are introduced. It is proved that in varieties with the congruence extension property, the weak interpolation property is equivalent to the weak amalgamation property. In turn, weak amalgamability of a variety is equivalent to amalgamability of a class of finitely generated simple algebras in this variety. Supported by RFBR (grant Nos. 06-01-00358 and 05-01-04003-NNIOa) and by INTAS (grant No. 04-77-7080). __________ Translated from Algebra i Logika, Vol. 47, No. 1, pp. 94–107, January–February, 2008.     

Weak normality properties and factorizations of normality

Summary Variants of δ-normality and δ-normal separation called weakly (functionally) δ-normal spaces are introduced and studied. This yields new factorizations of normality and δ-normality. A Urysohn type lemma and a Tietze type extension theorem for (weakly) functionally δ-normal spaces are obtained.     

The asymptotic normality of certain combinatorial distributions

Summary The numbersC(m, n, s) and |C(m, n, −s)|,s>0, appearing in then-fold convolution of truncated binomial and negative binomial distributions, respectively, are shown to be asymptotically normal. Moreover a concavity property for these numbers is concluded.     

Novel weak form quadrature element method with expanded Chebyshev nodes

Based on the principle of minimum potential energy and the differential quadrature rule, novel weak form quadrature element method is proposed. Different from the existing ones, expanded Chebyshev grid points are used as the element nodes. A simple but general way is proposed to compute the strains at the integration points explicitly by using the differential quadrature rule. For illustration and verification, quadrature bar and beam elements are established. Several examples are given. Numerical results indicate that the proposed quadrature element method allows a longer time step as compared to elements with other nodes and is an accurate and efficient method for structural analysis.     

A weak form quadrature element method for plane elasticity problems

A weak form quadrature element method is proposed and applied to analysis of plane elasticity problems. A variational formulation of plane elasticity problems is established and the differential quadrature analog of the derivatives in the functional is introduced. Several typical plane elasticity problems are studied to verify the proposed method. Results show that the method is highly efficient and promising. It is applied to the analysis of nearly incompressible materials and shown to be robust against volumetric locking. Similarities and dissimilarities, advantages and disadvantages as compared with other numerical methods, typically the p-version finite element method are discussed.     

Harmonicity of functions satisfying a weak form of the mean value property

Let W ì \Bbb Rⁿ\Omega \subset {\Bbb R}^n be a smooth domain and let u ? C⁰(W).u \in C^0(\Omega ). A classical result of potential theory states that¶¶-ò_{Sr([`(x)])</sub> u(x)ds(x)=u([`(x)])-\kern-5mm\int\limits _{S_{r}(\bar x)} u(x)d\sigma (x)=u(\bar x)¶¶for every [`(x)] ? W\bar x\in \Omega and r > 0r>0 if and only if¶¶Du=0 in W.\Delta u=0 \hbox { in } \Omega.¶¶Here -ò<sub>Sr([`(x)])} u(x)ds(x)-\kern-5mm\int\limits _{S_{r}(\bar x)} u(x)d\sigma (x) denotes the average of u on the sphere S_r([`(x)])S_r(\bar x) of center [`(x)]\bar x and radius r. Our main result, which is a "localized" version of the above result, states:¶¶Theorem. Let u ? W^2,1(W)u\in W^{2,1}(\Omega ) and let x ? Wx\in \Omega be a Lebesgue point of Du\Delta u such that¶¶-ò_Sr([`(x)]) u d s- a = o(r²)-\kern-5mm\int\limits _{S_{r}(\bar x)} u d \sigma - \alpha =o(r^2)¶¶for some a ? \Bbb R\alpha \in \Bbb R and all sufficiently small r > 0.r>0. Then¶¶Du(x)=0.\Delta u(x)=0.     

Upper bound limit analysis using the weak form quadrature element method

Limit analysis is a useful tool for design and safety assessment of structures in civil and geotechnical engineering. In the present study, a newly developed high order algorithm-the weak form quadrature element method is reformulated for upper bound limit analysis. The dual formulations of the kinematic theorem are employed with the nodal stresses chosen as the optimization variables. The weak form equilibrium constraint is numerically integrated by Lobatto integration and then the nodal derivatives are approximated by differential quadrature analogue. The resulting optimization problem is formulated as a standard second-order cone programming problem and solved by the optimization toolbox Mosek. This paper aims to improve the efficiency of the existing numerical limit algorithms especially for problems with singularities such as cracked structures and to overcome the well-known volumetric locking occurred for incompressible materials. Some numerical tests are given to show the accuracy and efficiency of the present method.     

Local asymptotic normality and mixed normality for Markov statistical models

Summary We prove local asymptotic normality (resp. local asymptotic mixed normality) of a statistical experiment, when the observation is a positive-recurrent (resp. null-recurrent, with an additional technical assumption) Markov chain or Markov step process, under rather mild regularity assumptions on the transition kernel for Markov chains, on the infinitesimal generator for Markov processes. The proof makes intensive use of Hellinger processes, thus avoiding almost completely to study the more complicated structure of the likelihoods themselves.