bluuebunny/crossref_metadata_2025_split huggingface dataset:
Variable D-marking on proper naming expressions: A typological study
Authors: Salaberri Iker 
Published: February 2021

AbstractRecent studies have argued that proper naming expressions cross-linguistically display distinct morphosyntactic behavior, i.e., naming-specific marking for case, definiteness, number and gender, among other categories. This study aims to contribute to the discussion by analyzing the marking of definiteness and specificity (D-marking) on naming expressions and common nouns from a comparative perspective, drawing on a sample of 50 areally, genetically and typologically diverse languages. The results present little support for D-marking being part of a cross-linguistically special onymic grammar: rather, the data suggest that there are different ways in which splits between common nouns and proper naming or between naming classes can materialize. Moreover, it is argued that the variability in D-marking of naming expressions correlates not just with animacy but with other semantic features as well, only some of which are integrated into the Animacy Hierarchy, including agentivity, individuation, identifiability and augmentation.
Novel Spurious Suppression Approach for SIR Dual-band Bandpass Filter Design
Authors: Chen Jianzhong , Li Xuefeng , Shi Hongyu , Zhang Anxue 
Published: February 2021

Abstract
A new design approach for a stepped impedance resonator (SIR) dual-band bandpass filter (BPF) with high multi-spurious suppression is proposed in this paper. The external coupling property of an SIR at multi-order resonant frequencies is fully studied. Different input impedances at desired frequencies are achieved by optimizing the unequal impedance transformer. The new solution shows the freedom in the choice of tapping point. The external quality values of multi-order harmonics vary with the shift of the tapping position. Wide upper stop-band rejection is realized by mismatching Qe at the unwanted harmonic frequencies, while keeping the Qe suitable for operating dual band to obtain good in-band performance. A traditional dual-band BPF and a novel practical BPF operated at 2.45/5.25 GHz are designed and fabricated to demonstrate the above idea. Good simulated and measured results are presented.
Radar based Ground Level Reconstruction Utilizing a Hypocycloid Antenna Positioning System
Authors: Baer Christoph , Musch Thomas 
Published: February 2021

Abstract
In this contribution we introduce a novel radar positioning system. It makes use of a mathematical curve, called hypocycloid, for a slanting movement of the radar antenna. By means of a planetary gear, a ball, and a universal joint as well as a stepping motor, a two dimensional positioning is provided by a uniaxial drive shaft exclusively. The fundamental position calculation and different signal processing algorithms are presented. By means of an 80 GHz FMCW radar system we performed several measurements on objects with discrete heights as well as on objects with continuous surfaces. The results of these investigations are essential part of this contribution and are discussed in detail.
Modeling Nonlinear White Noise in GaN HEMT Devices
Authors: Rudolph Matthias , Escotte Laurent , Doerner Ralf 
Published: February 2021

Abstract
This paper compares new bias-dependent descriptions for the Pucel and Pospieszalski noise models for GaN HEMT devices. It is proposed to replace the traditional descriptions of the noise sources by general noise powers linked to the drain current. A well-behaved bias dependence of the new parameters is observed for both models the new approach reduces uncertainty in the nonlinear noise model extraction. Finally, the performance of the bias-dependent noise models under nonlinear excitation is investigated and it can be shown that Pucel and Pospieszalski models yield comparably good accuracy in noise prediction.
On Conjugacy of High-Order Linear Ordinary Differential Equations
Authors: Chanturia T. 
Published: February 2021

Abstract
It is shown that the differential equation

u
(n) = p(t)u,
where n ≥ 2 and p : [a, b] → ℝ is a summable function, is not conjugate in the segment [a, b], if for some l ∈ {1, . . . , n – 1}, α ∈]a, b[ and β ∈]α, b[ the inequalities

hold.
A Second-Order Nonlinear Problem with Two-Point and Integral Boundary Conditions
Authors: Brykalov S. A. 
Published: February 2021

Abstract
The paper gives sufficient conditions for the existence and nonuniqueness of monotone solutions of a nonlinear ordinary differential equation of the second order subject to two nonlinear boundary conditions one of which is two-point and the other is integral. The proof is based on an existence result for a problem with functional boundary conditions obtained by the author in [Brykalov, Differential Equations 27: 1415-1420, 1991].
On the Modified Boundary Value Problem of De La Vallée-Poussin for Nonlinear Ordinary Differential Equations
Authors: Tskhovrebadze G. 
Published: February 2021

Abstract
The sufficient conditions of the existence, uniqueness, and correctness of the solution of the modified boundary value problem of de la Vallée-Poussin have been found for a nonlinear ordinary differential equation

u
(n) = f(t, u, u′, … , u
(n–1)),
where the function f has nonitegrable singularities with respect to the first argument.
Orthogonal Random Vectors and the Hurwitz-Radon-Eckmann Theorem
Authors: Vakhania N. 
Published: February 2021

Abstract
In several different aspects of algebra and topology the following problem is of interest: find the maximal number of unitary antisymmetric operators Ui
in with the property UiUj
= –UjUi
(i ≠ j). The solution of this problem is given by the Hurwitz-Radon-Eckmann formula. We generalize this formula in two directions: all the operators Ui
must commute with a given arbitrary self-adjoint operator and H can be infinite-dimensional. Our second main result deals with the conditions for almost sure orthogonality of two random vectors taking values in a finite or infinite-dimensional Hilbert space H. Finally, both results are used to get the formula for the maximal number of pairwise almost surely orthogonal random vectors in H with the same covariance operator and each pair having a linear support in H ⊕ H.
The paper is based on the results obtained jointly with N.P.Kandelaki (see [Vakhania and Kandelaki, Dokl. Akad. Nauk SSSR 294: 528-531, 1987, Dokl. Akad. Nauk SSSR 296: 265-266, 1988, Trudy Inst. Vychisl. Mat. Akad. Nauk Gruz. SSR 28: 11-37, 1988]).
Basic Boundary Value Problems of Thermoelasticity for Anisotropic Bodies with Cuts. I
Authors: Duduchava R. , Natroshvili D. , Shargorodsky E. 
Published: February 2021

Abstract
The three-dimensional problems of the mathematical theory of thermoelasticity are considered for homogeneous anisotropic bodies with cuts. It is assumed that the two-dimensional surface of a cut is a smooth manifold of an arbitrary configuration with a smooth boundary. The existence and uniqueness theorems for boundary value problems of statics and pseudo-oscillations are proved in the Besov and Bessel-potential spaces by means of the classical potential methods and the theory of pseudodifferential equations on manifolds with boundary. Using the embedding theorems, it is proved that the solutions of the considered problems are Hölder continuous. It is shown that the displacement vector and the temperature distribution function are Cα
-regular with any exponent α < 1/2.
This paper consists of two parts. In this part all the principal results are formulated. The forthcoming second part will deal with the auxiliary results and proofs.
On Some Boundary Value Problems with Integral Conditions for Functional Differential Equations
Authors: Kiguradze I. , Chichua D. 
Published: February 2021

Abstract
For the functional differential equation u
(n)(t) = ƒ(u)(t) we have established the sufficient conditions for solvability and unique solvability of the boundary value problems

and

where n ≥ 2, m is the integer part of , ci
∈ R, and ƒ is the continuous operator acting from the space of (n – 1)-times continuously differentiable functions given on an interval [0, +∞[ into the space of locally Lebesgue integrable functions.
The Cauchy–Nicoletti Problem with Poles
Authors: Werner T. 
Published: February 2021

Abstract
The Cauchy–Nicoletti boundary value problem for a system of ordinary differential equations with pole-type singularities is investigated. The conditions of the existence, uniqueness, and non-uniqueness of a solution in the class of continuously differentiable functions are given. The classical Banach contraction principle is combined with a special transformation of the original problem.
Basic Boundary Value Problems of Thermoelasticity for Anisotropic Bodies with Cuts. II
Authors: Duduchava R. , Natroshvili D. , Shargorodsky E. 
Published: February 2021

Abstract
In the first part [Duduchava, Natroshvili and Shargorodsky, Georgian Math. J. 2: 123–140, 1985] of the paper the basic boundary value problems of the mathematical theory of elasticity for three-dimensional anisotropic bodies with cuts were formulated. It is assumed that the two-dimensional surface of a cut is a smooth manifold of an arbitrary configuration with a smooth boundary. The existence and uniqueness theorems for boundary value problems were formulated in the Besov () and Bessel-potential () spaces. In the present part we give the proofs of the main results (Theorems 7 and 8) using the classical potential theory and the nonclassical theory of pseudodifferential equations on manifolds with a boundary.
On the Solvability of A Spatial Problem of Darboux Type for the Wave Equation
Authors: Kharibegashvili S. 
Published: February 2021

Abstract
The question of the correct formulation of one spatial problem of Darboux type for the wave equation has been investigated. The correct formulation of that problem in the Sobolev space has been proved for surfaces having a quite definite orientation on which are given the boundary value conditions of the problem of Darboux type.
On A Darboux Problem for A Third Order Hyperbolic Equation with Multiple Characteristics
Authors: Jokhadze O. 
Published: February 2021

Abstract
A Darboux type problem for a model hyperbolic equation of the third order with multiple characteristics is considered in the case of two independent variables. The Banach space , α ≥ 0, is introduced where the problem under consideration is investigated. The real number α
0 is found such that for α > α
0 the problem is solved uniquely and for α < α
0 it is normally solvable in Hausdorff's sense. In the class of uniqueness an estimate of the solution of the problem is obtained which ensures stability of the solution.
Commutativity for a Certain Class of Rings
Authors: Abujabal Hamza A. S. 
Published: February 2021

Abstract
We discuss the commutativity of certain rings with unity 1 and one-sided s-unital rings under each of the following conditions: xr
[xs, y] = ±[x, yt
]xn
, xr
[xs, y] = ±xn
[x, yt
], xr
[xs, y] = ±[x, yt
]ym
, and xr
[xs, y] = ±ym
[x, yt
], where r, n, and m are non-negative integers and t > 1, s are positive integers such that either s, t are relatively prime or s[x, y] = 0 implies [x, y] = 0. Further, we improve the result of [Jacobson, Structure of rings, Colloq. Publ., 1964, Theorem 3] and reprove several recent results.
Criteria of Unitary Equivalence of Hermitian operators with a Degenerate Spectrum
Authors: Lomidze I. 
Published: February 2021

Abstract
Nonimprovable, in general, estimates of the number of necessary and sufficient conditions for two Hermitian operators to be unitarily equaivalent in a unitary space are obtained when the multiplicities of eigenvalues of operators can be more than 1. The explicit form of these conditions is given. In the Appendix the concept of conditionally functionally independent functions is given and the corresponding necessary and sufficient conditions are presented.
On a Darboux Type Multidimensional Problem for Second-Order Hyperbolic Systems
Authors: Kharibegashvili S. 
Published: February 2021

Abstract
The correct formulation of a Darboux type multidimensional problem for second-order hyperbolic systems is investigated. The correct formulation of such a problem in the Sobolev space is proved for temporal type surfaces on which the boundary conditions of a Darboux type problem are given.
On the Correctness of the Cauchy Problem for a Linear Differential System on an Infinite Interval
Authors: Kiguradze I. 
Published: February 2021

Abstract
The conditions ensuring the correctness of the Cauchy problem

on the nonnegative half-axis R
+ are found, where P : R
+ → R

n×n
and q : R
+ → Rn
are locally summable matrix and vector functions, respectively, t
0 ∈ R
+ and c
0 ∈ Rn
.
On the Correctness of Nonlinear Boundary Value Problems for Systems of Generalized Ordinary Differential Equations
Authors: Ashordia M. 
Published: February 2021

Abstract
The concept of a strongly isolated solution of the nonlinear boundary value problem

dx(t) = dA(t) · f (t, x(t)), h(x) = 0,
is introduced, where A : [a, b] → Rn×n
is a matrix-function of bounded variation, f : [a, b] × Rn
→ Rn
is a vector-function belonging to a Carathéodory class, and h is a continuous operator from the space of n-dimensional vector-functions of bounded variation into Rn
.
It is stated that the problems with strongly isolated solutions are correct. Sufficient conditions for the correctness of these problems are given.
On Continuous Extensions
Authors: Narici Lawrence , Beckenstein Edward 
Published: February 2021

Abstract
We consider various possibilities concerning the continuous extension of continuous functions taking values in an ultrametric space. In Section 1 we consider Tietze-type extension theorems concerning continuous extendibility of continuous functions from compact and closed subsets to the whole space. In Sections 2 and 3 we consider extending “separated” continuous functions in such a way that certain continuous extensions remain separated. Functions taking values in a complete ultravalued field are dealt with in Section 2, and the real and complex cases in Section 3.
Weighted L
Φ Integral Inequalities for Maximal Operators
Authors: Rakotondratsimba Y. 
Published: February 2021

Abstract
Sufficient (almost necessary) conditions are given on the weight functions u(·), v(·) for

to hold when Φ1, Φ2 are -functions with subadditive , and Ms (0 ≤ s < n), is the usual fractional maximal operator.
Parametrization of a Family of Minimal Surfaces Bounded by the Broken Lines in
Authors: Abdulaev R. 
Published: February 2021

Abstract
Consideration is given to a family of minimal surfaces bounded by the broken lines in which are locally injectively projected onto the coordinate plane. The considered family is bijectively mapped by means of the Enepper–Weierstrass representation onto a set of circular polygons of a certain type. The parametrization of this set is constructed, and the dimension of the parameter domain is established.
On Singular Functional Differential Inequalities
Authors: Kiguradze I. , Sokhadze Z. 
Published: February 2021

Abstract
Classical theorems on differential inequalities [Coddington and Levinson, Theory of ordinary differential equations, Mc Graw-Hill Book Company, Inc., 1995, Hartman, Ordinary differential equations, John Wiley & Sons, 1964, Walter, Differential and integral inequalities, Springer-Verlag, 1970] are generalized for initial value problems of the kind

and

where ƒ : C([a, b]; Rn
) → Lloc
(]a, b]; Rn
) is a singular Volterra operator, c
0 ∈ Rn
, h : [a, b] → [0, +∞[ is continuous and positive on ]a, b], ‖ · ‖ is a norm in Rn
, and [u]+ and [u]– are respectively the positive and the negative part of the vector u ∈ Rn
.
A Multidimensional Singular Boundary Value Problem of the Cauchy–Nicoletti Type
Authors: Diblík J. 
Published: February 2021

Abstract
A two-point singular boundary value problem of the Cauchy–Nicoletti type is studied by introducing a two-point boundary value set and using the topological principle. The results on the existence of solutions whose graph lies in this set are proved. Applications and comparisons to the known results are given, too.
On the Absolute Convergence of Fourier Series
Authors: Karchava T. 
Published: February 2021

Abstract
The necessary and sufficient conditions of the absolute convergence of a trigonometric Fourier series are established for continuous 2π-periodic functions which in [0, 2π] have a finite number of intervals of convexity, and whose 𝑛th Fourier coefficients are O(ω(1/𝑛; 𝑓)/𝑛), where ω(δ; 𝑓) is the continuity modulus of the function 𝑓.
On the Global Solvability of the Cauchy Problem for Singular Functional Differential Equations
Authors: Kiguradze I. , Sokhadze Z. 
Published: February 2021

Abstract
Sufficient conditions are found for the global solvability of the weighted Cauchy problem

where 𝑓 : 𝐶([𝑎, 𝑏]; 𝑅𝑛) → 𝐿𝑙𝑜𝑐(]𝑎, 𝑏]; 𝑅𝑛) is a singular Volterra operator, 𝑐0 ∈ 𝑅𝑛, 𝑕 : [𝑎, 𝑏] → [0, +∞[ is a function continuous and positive on ]𝑎, 𝑏], and ∥ · ∥ is the norm in 𝑅𝑛.
On the Boundedness of Classical Operators on Weighted Lorentz Spaces
Authors: Rakotondratsimba Y. 
Published: February 2021

Abstract
Conditions on weights 𝑢(·), υ(·) are given so that a classical operator T sends the weighted Lorentz space Lrs
(υd𝑥) into Lpq
(υd𝑥). Here T is either a fractional maximal operator Mα
or a fractional integral operator Iα
or a Calderón–Zygmund operator. A characterization of this boundedness is obtained for Mα
and Iα
when the weights have some usual properties and max(r, s) ≤ min(p, q).
On Vitali's Theorem for Groups of Motions of Euclidean Space
Authors: Kharazishvili A. 
Published: February 2021

Abstract
We give a characterization of all those groups of isometric transformations of a finite-dimensional Euclidean space, for which an analogue of the classical Vitali theorem [Sul problema della misura dei gruppi di punti di una retta, 1905] holds true. This characterization is formulated in purely geometrical terms.
On Periodic Solutions of Nonlinear Functional Differential Equations
Authors: Kiguradze I. , Půža B. 
Published: February 2021

Abstract
Sufficient conditions are established for the existence and uniqueness of an ω-periodic solution of the functional differential equation

where f is a continuous operator acting from the space of n-dimensional ω-periodic continuous vector functions into the space of n-dimensional ω-periodic and summable on [0, ω] vector functions.
A Contact Problem of the Interaction of a Semi-Finite Inclusion with a Plate
Authors: Shavlakadze N. 
Published: February 2021

Abstract
A piecewise-homogeneous plane made up of twodifferent materials and reinforced by an elastic unclusion is considered on a semi-finite section where the different materials join. Vertical and horizontal forces are applied to the inclusion which haz a variable thichness and a variable elasticity modulus.
Under certain conditions the problem is reduced to integrodifferential equations of third order. The solution is constructed effectively by applying the methods of theory of analytic functions to a boundary value problem of the Carleman type for a strip. Asymptotic estimates of normal contact stress are obtained.
Properties 𝐴 and 𝐵 of 𝑛th Order Linear Differential Equations with Deviating Argument
Authors: Koplatadze R. , Kvinikadze G. , Stavroulakis I. P. 
Published: February 2021

Abstract
Sufficient conditions for the nth order linear differential equation
𝑢(𝑛) (𝑡) + 𝑝(𝑡)𝑢(τ(𝑡)) = 0, 𝑛 ≥ 2,
to have Property 𝐴 or Property 𝐵 are established in both the delayed and the advanced cases. These conditions essentially improve many known results not only for differential equations with deviating arguments but for ordinary differential equations as well.
Multiple Solutions of Generalized Multipoint Conjugate Boundary Value Problems
Authors: Wong Patricia J. Y. , Agarwal Ravi P. 
Published: February 2021

Abstract
We consider the boundary value problem
𝑦(𝑛) (𝑡) = 𝑃(𝑡, 𝑦), 𝑡 ∈ (0, 1)
𝑦(𝑗) (𝑡𝑖) = 0, 𝑗 = 0, . . . , 𝑛𝑖 – 1, 𝑖 = 1, . . . , 𝑟,
where 𝑟 ≥ 2, 𝑛𝑖 ≥ 1 for 𝑖 = 1, . . . , 𝑟, and 0 = 𝑡1 < 𝑡2 < ⋯ < 𝑡𝑟 = 1. Criteria are offered for the existence of double and triple ‘positive’ (in some sense) solutions of the boundary value problem. Further investigation on the upper and lower bounds for the norms of these solutions is carried out for special cases. We also include several examples to illustrate the importance of the results obtained.
Sufficient Conditions for the Oscillation of Bounded Solutions of A Class of Impulsive Differential Equations of Second Order with a Constant Delay
Authors: Bainov D. D. , Dimitrova M. B. 
Published: February 2021

Abstract
Sufficient conditions are found for oscillation of bounded solutions of a class of impulsive differential equations of second order with a constant delay. Some asymptotic properties are studied for the bounded solutions.
On the Number of Representations of Positive Integers by the Quadratic Form
Authors: Lomadze G. 
Published: February 2021

Abstract
An explicit exact (non asymptotic) formula is derived for the number of representations of positive integers by the quadratic form . The way by which this formula is derived, gives us a possibility to develop a method of finding the so-called Liouville type formulas for the number of representations of positive integers by positive diagonal quadratic forms in nine variables with integral coefficients.
Inequalities of Calderon–Zygmund Type for Trigonometric Polynomials
Authors: Runovski K. , Schmeisser H.-J. 
Published: February 2021

Abstract
We give a unified approach to inequalities of Calderon–Zygmund type for trigonometric polynomials of several variables based on the Fourier analytic methods. Sharp results are achieved for the full range of admissible parameters p, 0 < p ≤ +∞. The results obtained are applied to the problem of the image of the Fourier transform in the scale of Besov spaces.
On the Rationality of Certain Strata of the Lange Stratification of Stable Vector Bundles on Curves
Authors: Ballico E. 
Published: February 2021

Abstract
Let 𝑋 be a smooth projective curve of genus 𝑔 ≥ 2 and 𝑆(𝑟, 𝑑) the moduli scheme of all rank 𝑟 stable vector bundles of degree 𝑑 on 𝑋. Fix an integer 𝑘 with 0 < 𝑘 < 𝑟. H. Lange introduced a natural stratification of 𝑆(𝑟, 𝑑) using the degree of a rank 𝑘 subbundle of any 𝐸 ∈ 𝑆(𝑟, 𝑑) with maximal degree. Every non-dense stratum, say 𝑊(𝑘, 𝑟 – 𝑘, 𝑎, 𝑑 – 𝑎), has in a natural way a fiber structure ℎ : 𝑊(𝑘, 𝑟 – 𝑘, 𝑎, 𝑑 – 𝑎) → Pic𝑎(𝑋) × Pic𝑏(𝑋) with ℎ dominant. Here we study the rationality or the unirationality of the generic fiber of ℎ.
Some Problems of Thermoelastic Equilibrium of a Rectangular Parallelepiped in Terms of Asymmetric Elasticity
Authors: Khomasuridze N. 
Published: February 2021

Abstract
An effective solution of a number of boundary value and boundary contact problems of thermoelastic equilibrium is constructed for a homogeneous isotropic rectangular parallelepiped in terms of asymmetric and pseudo-asymmetric elasticity (Cosserat's continuum and pseudo- continuum). Two opposite faces of a parallelepiped are affected by arbitrary surface disturbances and a stationary thermal field, while for the four remaining faces symmetry or anti-symmetry conditions (for a multilayer rectangular parallelepiped nonhomogeneous contact conditions are also defined) are given. The solutions are constructed in trigonometric series using the method of separation of variables.
A Remark on Polygonal Quasiconformal Maps
Authors: Krushkal S. L. 
Published: February 2021

Abstract
Given a quasisymmetric map , let 𝑓0 be an extremal quasiconformal extension of ℎ onto the upper half-plane 𝘜 = {𝑧 ∈ ℂ : 𝔍𝑧 > 0} whose dilatation 𝑘(𝑓0) = inf{𝑘(𝑓) : 𝑓|∂𝘜 = ℎ0} ≕ 𝑘(ℎ). Let 𝑘𝑛 be the minimal dilatation of polygonal quasiconformal maps 𝑓 : 𝘜 → 𝘜 satisfying 𝑓(𝑥𝑗) = ℎ(𝑥𝑗), 𝑗 = 1, 2, . . . , 𝑛, for any 𝑛 points of (vertices of 𝑛-gons). Already a long time ago, the question was posed whether 𝑘(ℎ) = sup 𝑘𝑛, where the supremum is taken over all possible 𝑛-gons of such kind. The answer is obtained (in the negative) for the case of quadrilaterals (𝑛 = 4).
We show that in the case of pentagons (𝑛 = 5) the answer is also negative, i.e., there are quasisymmetric ℎ with 𝑘(ℎ) > sup 𝑘5.