Characterization of types of asymptotic discernibility of families of hypotheses

We give a characterization of the types of asymptotic discernibility of families of hypotheses in the case of hypothetical measures that are not, in general, mutually absolutely continuous. The case when the logarithm of the likelihood ratio admits an asymptotic expansion of the type of an expansion with local asymptotic normality is examined in detail. Examples are studied.Translated fromTeoriya Sluchainykh Protsessov, Vol. 15, pp. 64–71, 1987.     

Linear problems of the stability of a type of rotation of a satellite about the centre of mass

The stability in the first approximation of the rotation of a satellite about a centre of mass is investigated. In the unperturbed motion the satellite performs, in absolute space, three rotations around the normal to the orbital plane in a time equal to two periods of rotation of its centre of mass in the orbit (Mercury-type rotation). Three cases of such rotations are considered: the rotations of a dynamically symmetrical satellite and a satellite, the central ellipsoid of inertia of which is close to a sphere, in an elliptic orbit of arbitrary eccentricity, and the rotation of a satellite with three different principal central moments of inertia in a circular orbit.     

Asymptotic properties of the solutions of the equations of motion of gyroscopic systems

The motion of mechanical systems acted upon by gyroscopic and positional forces characterized by a large parameter in the corresponding equations of motion is considered. Periodic solutions of such equations were investigated earlier in [1, 2]. It is proved below that solutions of these equations exist, defined in an interval the length of which is a monotonically increasing unbounded function of the large parameter, and which transfer into the solutions of the corresponding degenerate systems as the large parameter approaches infinity. This function can be specified in more detail if additional assumptions are made regarding the properties of the system and the nature of the forces acting on it.     

Variational formulations of certain problems of the theory of the flow of rigid-plastic media

The mathematical content of variational problems of the mechanics of rigid-plastic media reduces to minimizing convex functionals in non-reflexive spaces of solenoidal vector fields. Different formulations are presented in /1/. Problems are examined there in which discontinuous velocity fields occur. The initial functional is undetermined in such fields. In this connection, the problem is posed of constructing that extension of the original set of kinematically allowable velocity fields as would contain all their possible discontinuities allowed by the mechanics of rigidly plastic media, and of continuing the original functional into the extension obtained. This problem is solved in this paper for the case when the velocity field is given on the whole surface of the rigid-plastic body.     

Existence of solutions of certain systems of non-linear inequalities

In recent years there has been increasing interest in the problem of the existence of solutions to systems of linear inequalities, however little has been done in the general case of non-linear inequalities. In this paper a certain class of non-linear inequalities is considered. Several existence theorems are established which generalize certain recent results in linear inequalities.     

Structure of genera of representations of nonsemisimple rings

The investigation of integral representations of arbitrary rings is shown to be equivalent to the case of orders in semisimple algebras. An example is constructed showing that, for an order in a nonsemisimple algebra, the number of representations in the genus may increase without limit with varying genera.Translated from Matematicheskie Zametki, Vol. 10, No. 1, pp. 63–87, July, 1971.     

Convergence of densities of some functionals of Gaussian processes

The aim of this paper is to establish the uniform convergence of the densities of a sequence of random variables, which are functionals of an underlying Gaussian process, to a normal density. Precise estimates for the uniform distance are derived by using the techniques of Malliavin calculus, combined with Stein?s method for normal approximation. We need to assume some non-degeneracy conditions. First, the study is focused on random variables in a fixed Wiener chaos, and later, the results are extended to the uniform convergence of the derivatives of the densities and to the case of random vectors in some fixed chaos, which are uniformly non-degenerate in the sense of Malliavin calculus. Explicit upper bounds for the uniform norm are obtained for random variables in the second Wiener chaos, and an application to the convergence of densities of the least square estimator for the drift parameter in Ornstein–Uhlenbeck processes is discussed.     

Region of linearity of the deformation properties of contact-molded glass-reinforced plastic

A study was made of the creep and recovery of contact-molded glass-reinforced plastic in different directions in the plane of the sheet in uniaxial tension. On the basis of experimental data, the region of linearity of the deformation properties of the material under investigation was established. The influence functions in the relations of the theory of viscoelasticity were taken in the form proposed by Bronskii. The dependence of the parameters which determine these functions on direction was investigated. It is shown that, in practice, this dependence is inherent in only one of the parameters, and a relationship which is in satisfactory agreement with the experimental results is proposed to describe it.Moscow Institute of Chemical Machine Building. Scientific-Research Institute for Mechanics, M. V. Lomonosov State University, Moscow. Translated from Mekhanika Polimerov, No. 3, pp. 404–410, May–June, 1970.     

Some applications of the condensation of the singularities of families of nonnegative functions

RecentlyPrus-Wi?niowski [14] has proved that the continuous functions of Λ-bounded variation on [0, 1] form a set of the first category in the Banach space C[0, 1] and also in each Banach space CΓBV[0, 1] of continuous functions of Γ-bounded variation on [0, 1] provided that the sequence Γ is adequate. In the present paper these results are extended and completed by using a principle of the condensation of the singularities of a family of nonnegative functions that follows from the theorems given byBreckner [3]. It is shown that Baire category properties similar to those stated in [14] are valid for two very large classes of real-valued functions called functions of bounded λ-variation of orderp and functions of boundedmth variation of orderp, respectively. The benefit of considering these classes is that they comprise several classes of functions of bounded variation type which have occurred so far in Fourier analysis or real analysis; in particular, the functions investigated in [14]. Thus, by specializing the results derived in the present paper, they give at once Baire category information concerning a number of well-known sets of real-valued functions.     

Smallest constant of extension of functions of Sobolev classes

The problem is posed on the class-preserving extension of functions of Sobolev class is a finite domain in the in-dimensional space) onto the whole of such that the supports of the extended functions would lie in a specified finite domain and such that the so-called constant of extension would be minimal. The existence of such an extension is proved under constraints on of the type of a certain minimal smoothness; an algorithm for the approximate computation of the minimal constant of extension is indicated forp=2. Ifp=2 andS=I while are concentric balls, then the exact value of the constant of extension has been computed under the usual definition of a norm in; it is expressed in terms of Bessel functions of an imaginary argument. The exact value mentioned permits the estimation from above and from below of the constant of extension in the case when the domain is diffeomorphic to a sphere.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 90, pp. 150–185, 1979.     

Combined use of the method of thermoplasticity and the method of the shrinkage function for the study of the process of thermal straightening of shipbuilding panels

We present an approach to the combined use of the general method of thermoplasticity and the approximate method of the shrinkage function for predicting total distortions of large-sized spatial structures in welding or thermal straightening. The proposed approach is particularly efficient in the case of a large number of welded joints in the structure or local heatings in thermal straightening. An example of using the approach in the study of the efficiency of the process of thermal straightening of shipbuilding panels is presented.     

Asymptotic growth of codimensions of identities of associative algebras

Numerical characteristics of identities of associative and non-associative algebras are studied in the paper. It is announced that the sequence of codimensions of an arbitrary associative PI-algebra asymptotically increases and that this is not true in the general non-associative case.     

Theory of the biomechanism of fractures of the diaphysis of long tubular bones

A new theoretical basis is proposed for the biomechanism of fractures of the diaphysis of long tubular bones resulting from bending deformation. Bone damage is shown to result from the concentration of maximum tensile stresses on the tension side and shear stresses in the compression zone. The origin of fan-shaped cracks and oblique fractures, occurring individually or in combination, is explained in these terms.Altai State Medical Institute. Translated from Mekhanika Polimerov, No. 2, pp. 318–322, March–April, 1971.     

The use of splitting of the equations of motion in the numerical solution of problems of the dynamics of elastic systems

Linear elastic systems with a finite number of degrees of freedom, the initial equations of motion of which are constructed using the finite element method or other discretization methods, are considered. Since, in applied dynamics problems, the motions are usually investigated in a frequency range with an upper bound, the degrees of freedom of the initial system of equations are split into dynamic and quasi-dynamic degrees. Finally, the initial system of equations is split into a small number of differential equations for the dynamic degrees of freedom and into a system of algebraic equations for determining the quasi-static displacements, represented in the form of a matrix series. The number of terms of the series taken into account depends on the accuracy required.     

Regularity of the sample paths of a class of second-order spde's

We study the sample path regularity of the solutions of a class of spde's which are second order in time and that includes the stochastic wave equation. Non-integer powers of the spatial Laplacian are allowed. The driving noise is white in time and spatially homogeneous. Continuing with the work initiated in Dalang and Mueller (Electron. J. Probab. 8 (2003) 1), we prove that the solutions belong to a fractional L²-Sobolev space. We also prove Hölder continuity in time and therefore, we obtain joint Hölder continuity in the time and space variables. Our conclusions rely on a precise analysis of the properties of the stochastic integral used in the rigourous formulation of the spde, as introduced by Dalang and Mueller. For spatial covariances given by Riesz kernels, we show that our results are optimal.     

神经脉冲传导的一种解与动作势的稳定性

本文提出神经脉冲动作势所遵从的一种规律,用普遍的形式——非线性耗散过程进行讨论.在小耗散的情况下,得到神经波是一种慢变振幅的孤立波;在通常量级耗散的情况下,证明了不能形成孤立子,而得到变幅的行波,在过阻尼的情况下,讨论了各种可能平衡动作势的稳定性及分叉现象.     

Chronology of Mesozoic volcanics of India

K-Ar ages of a number of samples from Rajmahal and Deccan Traps and from basaltic dykes of Gondwanas have been measured. The results suggest that the Early Rajmahals erupted in the middle of early Cretaceous (～ 110 my) and probably continued to be active till the end of Cretaceous. Deccan activity started in Gujarat-Kathiawar area in Early Paleocene and spread over almost the entire area in next 5–7 my. However, in the north-eastern region of the traps around Chindwara and Amarkantak, the basalts were laid in the middle of the Eocene (～ 47 my). The measured ages of Deccan dykes suggest a subdued hypabyssal activity continuing till the end of Eocene or beyond. The K-Ar ages of Gondwana extrusions exhibit contemporaneity with Deccan activity even for the dykes which are located right close to the Rajmahal outcrops; indicating no regular drift of the foci of volcanic activity. A distant dyke from Cuttack gives an early Rajmahal age, and therefore probably indicates the vast extent to which Rajmahal activity manifested itself.     

Stability of solutions of monotone systems of impulsive differential equations

We obtain sufficient conditions for the stability of solutions of nonlinear systems of impulsive differential equations in a cone. The main tool in our study is the comparison principle suggested in the paper. This approach permits one to study critical cases; it is illustrated by examples of nonlinear systems for which the trivial orbit of the continuous and discrete components is simultaneously unstable.     

Certain versions of the formulation of problems of non-linear elasticity in terms of stresses

New versions of the formulation of static non-linear elasticity theory problems are elucidated in terms of stresses for materials with locally reversible state laws (for instance, for a semilinear John material /1/), that reduce to the solution of nine equations in the Piola stress tensor component for six or three boundary conditions and three integral conditions. This paper is related to the investigations in /2–7/ devoted to analogous problems of the mechanics of a solid linearly deformable body. Examples are presented of the realization of one of the versions.     

Growth of primary decompositions of Frobenius powers of ideals

It was previously known, by work of Smith–Swanson and of Sharp–Nossem, that the linear growth property of primary decompositions of Frobenius powers of ideals in rings of prime characteristic has strong connections to the localization problem in tight closure theory. The localization problem has recently been settled in negative by Brenner and Monsky, but the linear growth question is still open. We study growth of primary decompositions of Frobenius powers of dimension one homogeneous ideals in graded rings over fields. If the ring is positively graded we prove that the linear growth property holds. For non-negatively graded rings we are able to show that there is a “polynomial growth”. We present explicit primary decompositions of Frobenius powers of an ideal, which were known to have infinitely many associated primes, having this linear growth property. We also discuss some other interesting examples.