bluuebunny/crossref_metadata_2025_split huggingface dataset:
Species separation within the Lessonia nigrescens complex (Phaeophyceae, Laminariales) is mirrored by ecophysiological traits
Authors: Koch Kristina , Thiel Martin , Tellier Florence , Hagen Wilhelm , Graeve Martin , Tala Fadia , Laeseke Philipp , Bischof Kai 
Published: February 2021

Abstract

Lessonia nigrescens used to be an abundant kelp species along the Chilean coast, but recent molecular studies revealed the existence of a L. nigrescens species complex, which includes the two cryptic species Lessonia berteroana and Lessonia spicata. Since these species have different distributions (16°S–30°S for L. berteroana and 29°S–42°S for L. spicata), they experience differences in environmental conditions, such as solar irradiance, seawater temperature and air exposure during low tide. This study tested to what extent the genetic distinctness of each of the two species [identified by a mitochondrial marker (atp8/trnS)] is reflected by ecophysiological traits (total lipids, fatty acid composition, phlorotannins, pigments and variable chlorophyll a fluorescence of PSII) in response to the respective environmental conditions, prevailing along the latitudinal gradient. We studied algal individuals from eight populations (27°S–32°S, including the species overlapping zone). Phlorotannins, pigments and Chl a fluorescence of PSII were most crucial for species-specific adaptations at the respective growth sites, whereas changes in total lipids and fatty acid compositions were negligible. Hence, species differentiation within the L. nigrescens complex is also manifested at the ecophysiological level. These findings may help to predict kelp responses towards future environmental changes.
Innus: A God of Archaic Latium and His Sanctuary at Fosso dell’Incastro (Ardea)
Authors: Torelli Mario 
Published: February 2021

Abstract
In 2006, the Soprintendenza Archeologica del Lazio began an excavation at the site of Fosso dell’Incastro on the coastline of Ardea. A well-preserved settlement buried under huge sand dunes was discovered, featuring a Roman castrum created in the fourth century BCE around a sanctuary dating back to the mid-sixth century BCE. Its characteristics not only suggested that the ancient site was Castrum Inui, previously known only through the ancient literary sources (e.g., Virgil, Servius and Macrobius), but also that its sanctuary could be attributed to an inconspicuous local deity, Inuus—often correlated with Pan and Sol. In its final phase (the early Imperial period), the sanctuary housed three sacred buildings: Temple A, Temple B, and a small shrine dedicated to Aesculapius. Temple B, the site of Inuus’ worship, was constructed in the Etrusco-Italic style during the first quarter of the fifth century BCE, while Temple A was built during the mid-second century BCE. Temple B was oriented to the southwest, one typical for religious buildings connected to chthonic cults; two altars built during the fourth century BCE were placed along the façade of the temple, one facing the east and on the axis of the temple, the second close to its southwest corner. It was also enhanced with an acroterion depicting the head of a warrior with the skin and horns of a goat or cow over his helmet, a motif that establishes a connection between Innus, Pan and Faunus. Temple A, on the other hand, faced the northeast and was enhanced with a sculpted pediment in high relief showing an assembly of gods and possibly Aeneas. Both its orientation and the iconography of the pediment suggest that it was dedicated to Aeneas Indiges, a pan-Latin version of the old cult of Inuus.
Excavations at Poggio Civitate (Murlo) During the 2012--2013 Seasons: Domestic Architecture and Selected Finds From the Civitate A Property Zone
Authors: Tuck Anthony , Kreindler Kate , Huntsman Theresa 
Published: February 2021

Abstract
Excavations over the course of the 2012 and 2013 seasons at Poggio Civitate (Murlo) have revealed the presence of domestic architecture in an area immediately to the southwest of the Piano del Tesoro plateau, the portion of Poggio Civitate that preserves evidence of monumental building from the Orientalizing and Archaic phases of the site’s occupation. At least two building phases have been discovered in the eastern extent of the hill’s Civitate A property zone and they reveal that a small rectilinear structure dating to the late seventh century BCE was superimposed on an earlier, curvilinear structure. These architectural discoveries indicate that the opulent Orientalizing structures on the Piano del Tesoro plateau were not only visible to people on nearby hilltops, but also to a community that stood to its immediate west. While additional excavation is needed to clarify a number of questions about Civitate A, it is striking that its inhabitants appear to have had access to at least a few items of notable quality and potential social value, many of which were also used by the social elite living on the plateau. In addition, the number of planed, cut and carved antler, horn and bone objects and fragments recovered within the interior area of Structure 1 raises the possibility that artisans employed in the service of Poggio Civitate’s ruling elite created similar artifacts for their own domestic arena. Future excavations both in Civitate A as well as on other hilltop settlements in the region of Murlo should provide even greater insight into these and many other questions concerning this remarkably well-preserved site and the activities of its ancient inhabitants.
Dogon reported discourse markers: The Ben Tey quotative topicalizer
Authors: Hantgan Abbie 
Published: February 2021

Abstract
The purpose of this study is to re-evaluate the interpretation of a particle that has hitherto been analyzed as a marker either of addressee or the subject of a quoted clause in Ben Tey (Dogon, Mali). As both of these interpretations are typologically rare if not unique, a broader conceptualization for the particle as a quotative topic marker is proposed here. Data are from a newly compiled cross-linguistic annotated corpus of discourse reports within textual contexts. Along with data presentation and analysis, a methodology is illustrated for multilingual comparative corpus construction for the analysis of discourse reporting strategies.
On Two-Point Boundary Value Problems for Systems of Higher-Order Ordinary Differential Equations with Singularities
Authors: Kiguradze I. , Tskhovrebadze G. 
Published: February 2021

Abstract
The sufficient conditions of solvability and unique solvability of the two-point boundary value problems of Vallèe-Poussin and Cauchy-Niccoletti have been found for a system of ordinary differential equations of the form

u
(n) = ƒ(t, u, u′, . . . , u
(n – 1)),
where the vector function has nonintegrable singularities with respect to the first argument at the points a and b.
Applications of the Method of Barriers II. Some Singularly Perturbed Problems
Authors: Sushko V. G. , Rozov N. Kh. 
Published: February 2021

Abstract
The method of barriers is used to justify asymptotic representations of solutions of two-point boundary value problems for singularly perturbed quasilinear equations of the second and the third order. This paper is a continuation of [Rozov and Sushko, Georgian Math. J. 2: 99-110, 1995].
On a Problem of Littlewood
Authors: Khazaradze M. 
Published: February 2021

Abstract
The theorem on the tending to zero of coefficients of a trigonometric series is proved when the L
1-norms of partial sums of this series are bounded. It is shown that the analog of Helson's theorem does not hold for orthogonal series with respect to the bounded orthonormal system. Two facts are given that are similar toWeis' theorem on the existence of a trigonometric series which is not a Fourier series and whose L
1-norms of partial sums are bounded.
Weighted Composition Operators on Bergman and Dirichlet Spaces
Authors: Mirzakarimi G. , Seddighi K. 
Published: February 2021

Abstract
Let 𝐻(Ω) denote a functional Hilbert space of analytic functions on a domain Ω. Let 𝑤 : Ω → 𝐂 and ϕ : Ω → Ω be such that 𝑤 𝑓 ○ ϕ is in 𝐻(Ω) for every 𝑓 in 𝐻(Ω). The operator 𝑤𝐶
ϕ
Given by 𝑓 → 𝑤 𝑓 ○ ϕ is called a weighted composition operator on 𝐻(Ω). In this paper we characterize such operators and those for which (𝑤𝐶
ϕ
)* is a composition operator. Compact weighted composition operators on some functional Hilbert spaces are also characterized. We give sufficient conditions for the compactness of such operators on weighted Dirichlet spaces.
Internal Categories in a Left Exact Cosimplicial Category
Authors: Pataraia D. 
Published: February 2021

Abstract
The notion of an internal category in a left exact cosimplicial category is introduced. For any topos over sets a certain left exact cosimplicial category is constructed functorially and the category of internal categories in it is investigated. The notion of a fundamental group is defined for toposes admitting the notion of “a discrete category.”
On the Universal C*-Algebra Generated by Partial Isometry
Authors: Kandelaki T. 
Published: February 2021

Abstract
A universal C*-algebra is constructed which is generated by a partial isometry. Using grading on this algebra we construct an analog of Cuntz algebras which gives a homotopical interpretation of KK-groups. It is proved that this algebra is homotopy equivalent up to stabilization by 2×2 matrices to M
2(C). Therefore those algebras are KK-isomorphic.
Solution of Some Weight Problems for the Riemann–Liouville and Weyl Operators
Authors: Meskhi A. 
Published: February 2021

Abstract
The necessary and sufficient conditions are found for the weight function 𝑣, which provide the boundedness and compactness of the Riemann–Liouville operator 𝑅
α
from 𝐿𝑝 to . The criteria are also established for the weight function 𝑤, which guarantee the boundedness and compactness of the Weyl operator 𝑊
α
from to 𝐿𝑞.
Characterization of a Two-Weighted Vector-Valued Inequality for Fractional Maximal Operators
Authors: Rakotondratsimba Y. 
Published: February 2021

Abstract
We give a characterization of the weights 𝑢(·) and 𝑣(·) for which the fractional maximal operator 𝑀𝑠 is bounded from the weighted Lebesgue spaces 𝐿𝑝(𝑙𝑟, 𝑣𝑑𝑥) into 𝐿𝑞(𝑙𝑟, 𝑢𝑑𝑥) whenever 0 ≤ 𝑠 < 𝑛, 1 < 𝑝, 𝑟 < ∞, and 1 ≤ 𝑞 < ∞.
On Some Rings of Arithmetical Functions
Authors: Bhattacharjee D. 
Published: February 2021

Abstract
In this paper we consider several constructions which from a given 𝐵-product *𝐵 lead to another one . We shall be interested in finding what algebraic properties of the ring 𝑅𝐵 = 〈𝐶ℕ, +, *𝐵〉 are shared also by the ring . In particular, for some constructions the rings 𝑅𝐵 and will be isomorphic and therefore have the same algebraic properties.
Positive Solutions to Second Order Singular Differential Equations Involving the One-Dimensional M-Laplace Operator
Authors: Tanigawa Tomoyuki 
Published: February 2021

Abstract
We consider a class of second order quasilinear differential equations with singular ninlinearities. Our main purpose is to investigate in detail the asymptotic behavior of their solutions defined on a positive half-line. The set of all possible positive solutions is classified into five types according to their asymptotic behavior near infinity, and sharp conditions are established for the existence of solutions belonging to each of the classified types.
Oscillation and Nonoscillation Criteria for a Second Order Linear Equation
Authors: Chantladze T. , Kandelaki N. , Lomtatidze A. 
Published: February 2021

Abstract
New oscillation and nonoscillation criteria are established for the equation
𝑢″ + 𝑝(𝑡)𝑢 = 0,
where 𝑝 : ]1, + ∞[ → 𝑅 is the locally integrable function. These criteria generalize and complement the well known criteria of E. Hille, Z. Nehari, A. Wintner, and P. Hartman.
Derivative Uniform Sampling via Weierstrass σ(z). Truncation Error Analysis in
Authors: Pogány Tibor K. 
Published: February 2021

Abstract
In the entire functions space consisting of at most second order functions such that their type is less than πq/(2s
2) it is valid the q-order derivative sampling series reconstruction procedure, reading at the von Neumann lattice {s(m + ni)| (m, n) ∈ } via the Weierstrass σ(·) as the sampling function, s > 0. The uniform convergence of the sampling sums to the initial function is proved by the circular truncation error upper bound, especially derived for this reconstruction procedure. Finally, the explicit second and third order sampling formulæ are given.
Optimal Mean-Variance Robust Hedging under Asset Price Model Misspecification
Authors: Toronjadze T. 
Published: February 2021

Abstract
The problem of constructing robust optimal in the mean-variance sense trading strategies is considered. The approach based on the notion of sensitivity of a risk functional of the problem w.r.t. small perturbation of asset price model parameters is suggested. The optimal mean-variance robust trading strategies are constructed for one-dimensional diffusion models with misspecified volatility.
On Normal Approximation of Large Products of Functions: A Refinement of Blackwell's Result
Authors: Lo Albert Y. , Sazonov V. V. 
Published: February 2021

Abstract
An asymptotic expansion for the approximation of standardized products of large numbers of smooth positive functions by exp(–𝑥2/2) is given. This result is closely related to the Bernstein–von Mises theorem on the normal approximation of posterior distributions.
Asymptotic Behavior of Singular and Entropy Numbers for Some Riemann–Liouville Type Operators
Authors: Meskhi A. 
Published: February 2021

Abstract
The asymptotic behavior of the singular and entropy numbers is established for the Erdelyi–Köber and Hadamard integral operators (see, e.g., [Samko, Kilbas and Marichev, Integrals and derivatives. Theoryand Applications, Gordon and Breach Science Publishers, 1993]) acting in weighted L
2 spaces. In some cases singular value decompositions are obtained as well for these integral transforms.
Weight Inequalities for Singular Integrals Defined on Spaces of Homogeneous and Nonhomogeneous Type
Authors: Edmunds D. E. , Kokilashvili V. , Meskhi A. 
Published: February 2021

Abstract
Optimal sufficient conditions are found in weighted Lorentz spaces for weight functions which provide the boundedness of the Calderón–Zygmund singular integral operator defined on spaces of homogeneous and nonhomogeneous type.
On the Existence of Singular Solutions
Authors: Bartušek M. , Osička J. 
Published: February 2021

Abstract
Sufficient conditions are given, under which the equation 𝑦(𝑛) = ƒ(𝑡, 𝑦, 𝑦′, . . . , 𝑦(𝑙))𝑔(𝑦(𝑛 – 1)) has a singular solution 𝑦[𝑇, τ) → 𝐑, τ < ∞ satisfying , 𝑖 = 0, 1, . . . , 𝑙 and for 𝑗 = 𝑙 + 1, . . . , 𝑛 – 1 where 𝑙 ∈ {0, 1, . . . , 𝑛 – 2}.
Unilateral Contact of Elastic Bodies (Moment Theory)
Authors: Gachechiladze R. 
Published: February 2021

Abstract
Boundary contact problems of statics of the moment (couple-stress) theory of elasticity are studied in the case of a unilateral contact of two elastic anisotropic nonhomogeneous media. A problem, in which during deformation the contact zone lies within the boundaries of some domain, and a problem, in which the contact zone can extend, are given a separate treatment. Concrete problems suitable for numerical realizations are considered.
On the Representation of Numbers by the Direct Sums of Some Quaternary Quadratic Forms
Authors: Kachakhidze N. 
Published: February 2021

Abstract
The systems of bases are constructed for the spaces of cusp forms S
2m
(Γ0(5), χ

m
) and S
2m
(Γ0(13), χ

m
) for an arbitrary integer m ≥ 2. Formulas are obtained for the number of representations of a positive integers by the direct sums of some quaternary quadratic forms.
On Local Invariants of Totally Real Surfaces
Authors: Khimshiashvili G. 
Published: February 2021

Abstract
A class of totally real surface singularities is introduced for which one can define local topological invariants. The main result yields an algebraic estimate for the self-intersection index of a totally real germ. It is derived from an algebraic upper estimate for the index of a quasi-homogeneous vector field which generalizes the previously known estimates in terms of the so-called Petrovsky numbers.
On Some Properties of 𝑟-Maximal Sets and 𝑄1–𝑁-Reducibility
Authors: Omanadze R. 
Published: February 2021

Abstract
It is shown that if 𝑀1, 𝑀2 are 𝑟-maximal sets and 𝑀1 ≡ 𝑄1–𝑁𝑀2, then 𝑀1 ≡ 𝑚𝑀2. In addition, we prove that there exists a simultaneously 𝑄1–𝑁- and 𝑊-complete recursively enumerable set which is not 𝑠𝑄-complete.
On Appel-Type Quadrature Rules
Authors: Belingeri C. , Germano B. 
Published: February 2021

Abstract
The Radon technique is applied in order to recover a quadrature rule based on Appel polynomials and the so called Appel numbers. The relevant formula generalizes both the Euler-MacLaurin quadrature rule and a similar rule using Euler (instead of Bernoulli) numbers and even (instead of odd) derivatives of the given function at the endpoints of the considered interval. In the general case, the remainder term is expressed in terms of Appel numbers, and all derivatives appear. A numerical example is also included.
On Fourier Series in Eigenfunctions of Elliptic Boundary Value Problems
Authors: Agranovich M. S. , Amosov B. A. 
Published: February 2021

Abstract
We consider a general elliptic formally self-adjoint problem in a bounded domain with homogeneous boundary conditions under the assumption that the boundary and coefficients are infinitely smooth. The operator in 𝐿2(Ω) corresponding to this problem has an orthonormal basis {𝑢𝑙} of eigenfunctions, which are infinitely smooth in . However, the system {𝑢𝑙} is not a basis in Sobolev spaces 𝐻𝑡 (Ω) of high order.
We note and discuss the following possibility: for an arbitrarily large 𝑡, for each function 𝑢 ∈ 𝐻𝑡 (Ω) one can explicitly construct a function 𝑢0 ∈ 𝐻𝑡 (Ω) such that the Fourier series of the difference 𝑢 – 𝑢0 in the functions 𝑢𝑙 converges to this difference in 𝐻𝑡 (Ω). Moreover, the function 𝑢(𝑥) is viewed as a solution of the corresponding nonhomogeneous elliptic problem and is not assumed to be known a priori; only the right-hand sides of the elliptic equation and the boundary conditions for 𝑢 are assumed to be given.
These data are also sufficient for the computation of the Fourier coefficients of 𝑢 – 𝑢0. The function 𝑢0 is obtained by applying some linear operator to these right-hand sides.
Oscillation and Nonoscillation Criteria for two-Dimensional Systems of Linear Ordinary Differential Equations
Authors: Polák L. 
Published: February 2021

Abstract
Sufficient conditions are established for the oscillation and nonoscillation of the system
𝑢′ = 𝑞(𝑡)𝑣,
𝑣′ = –𝑝(𝑡)𝑢,
where 𝑝, 𝑞 : [0, +∞[→] – ∞, +∞[ are locally summable functions, 𝑞(𝑡) ≥ 0 for 𝑡 ≥ 0, and .
The Predifferential of a Path Fibration
Authors: Berikashvili N. , Mikiashvili M. 
Published: February 2021

Abstract
For a simply connected space 𝐵 the Hirsch model of path fibration is constructed in terms of 𝐵. In particular this means the calculation of loop space cohomology. As an application, the Hirsch model of the fiber of any fibration over 𝐵 is given.
Wintner-Type Oscillation Criteria of Semilinear Elliptic Inequalities
Authors: Xu Zhiting 
Published: February 2021

Abstract
Wintner-type oscillation criteria of semilinear elliptic inequalities are obtained by using partial Riccati technique. The results presented improve the oscillation criteria due to E. S. Noussair and C.A. Swanson [Canad. J. Math. 32: 908–923, 1980].
Uniform and 𝐿-Convergence of Logarithmic Means of Double Walsh–Fourier Series
Authors: Gát György , Goginava Ushangi 
Published: February 2021

Abstract
We discuss some convergence and divergence properties of twodimensional (Nörlund) logarithmic means of two-dimensional Walsh–Fourier series of functions both in the uniform and in the Lebesgue norm. We give necessary and sufficient conditions for the convergence regarding the modulus of continuity of the function, and also the function space.
A Generalization of Bihari's Lemma for Discontinuous Functions and Its Application to the Stability Problem of Differential Equations with Impulse Disturbance
Authors: Borysenko Sergiy , Matarazzo Giovanni , Pecoraro Massimo 
Published: February 2021

Abstract
This paper presents a generalization of nonlinear integral inequalities of the Gronwall–Bellman–Bihari type for discontinuous functions and its application to the investigation of the practical stability of solutions of systems of integro-differential equations with impulse perturbations at fixed moments of time.
The Potential Method for the Reactance Wave Diffraction Problem in a Scale of Spaces
Authors: Castro Luis P. , Natroshvili David 
Published: February 2021

Abstract
This paper is concerned with a screen type boundary value problem arising from the wave diffraction problem with a reactance condition. We consider the problem in a weak formulation within Bessel potential spaces, and where both cases of a complex and a pure real wave number are analyzed. Using the potential method, the boundary value problem is converted into a system of integral equations. The invertibility of the corresponding matrix pseudodifferential operator is shown in appropriate function spaces which allows the conclusion about the existence and uniqueness of a weak solution to the original problem. Higher regularity properties of solutions are also proved to exist in some scale of Bessel potential spaces, upon the corresponding smoothness improvement of given data. In particular, the 𝐶
α
-smoothness of solutions in a neighbourhood of the screen edge is established with arbitrary α < 1 in the two-dimensional case and α < 1/2 in the three-dimensional case.
An Inverse Result in Simultaneous Approximation by Modified Beta Operators
Authors: Maheshwari Prerna 
Published: February 2021

Abstract
In this paper we study the modified Beta operators. We extend the result of [Gupta and Ahmad, İstanbul niv. Fen Fak. Mat. Derg. 54: 11–22 1995] and obtain an inverse result for the linear combination of these modified Beta operators in simultaneous approximation.
Exact Distributions of the Product and Ratio of Absolute Values of Pearson Type VII and Bessel Function Random Variables
Authors: Nadarajah Saralees , Kotz Samuel 
Published: February 2021

Abstract
Exact distributions of |𝑋𝑌| and |𝑋/𝑌| are derived when 𝑋 and 𝑌 are Pearson type VII and Bessel function random variables distributed independently of each other.
An Automatically Stable and Order Three Split Rational Approximation of a Semigroup
Authors: Rogava Jemal , Tsiklauri Mikheil 
Published: February 2021

Abstract
An automatically stable and order three split rational approximation scheme is proposed for solving the Cauchy abstract problem. The third order precision is obtained by introducing the complex parameter and performing a rational approximation of the semigroup. For the considered scheme, an explicit a priori estimate is derived.
Selfadjoint Operators and Generalized Central Algorithms in Frechet Spaces
Authors: Tsotniashvili Soso , Zarnadze David 
Published: February 2021

Abstract
The paper gives an extension of the fundamental principles of selfadjoint operators in Fréchet–Hilbert spaces, countable-Hilbert and nuclear Fréchet spaces. Generalizations of the well known theorems of von Neumann, Hellinger–Toeplitz, Friedrichs and Ritz are obtained. Definitions of generalized central and generalized spline algorithms are given. The restriction 𝐴∞ of a selfadjoint operator 𝐴 defined on a dense set 𝐷(𝐴) of the Hilbert space 𝐻 to the Frechet space 𝐷(𝐴∞) is substantiated. The extended Ritz method is used for obtaining an approximate solution of the equation 𝐴∞𝑢 = 𝑓 in the Frechet space 𝐷(𝐴∞). It is proved that approximate solutions of this equation constructed by the extended Ritz method do not depend on the number of norms that generate the topology of the space 𝐷(𝐴∞). Hence this approximate method is both a generalized central and generalized spline algorithm.
Examples of selfadjoint and positive definite elliptic differential operators satisfying the above conditions are given. The validity of theoretical results in the case of a harmonic oscillator operator is confirmed by numerical calculations.