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The paper introduces the notion of normal ring sets and considers the problem of decomposition and composition for them. [ABSTRACT FROM AUTHOR]

Let TH be the space of ( T + H)-matrices of order n. The paper considers the following question: Which unitary matrices U satisfy the condition ∀A ∈ TH → U* AU ∈ TH? A criterion for verifying whether a given matrix U has this property is proposed. Bibliography: 4 titles. [ABSTRACT FROM AUTHOR]

This paper is a review of studies in differential geometry of distributions for 35 years (1975-2009) based on abstracts published in the review journal 'Referativny Zhurnal, Series Mathematics.' [ABSTRACT FROM AUTHOR]

The split variational inclusion problem is an important problem, and it is a generalization of the split feasibility problem. In this paper, we present a descent-conjugate gradient algorithm for the split variational inclusion problems in Hilbert spaces. Next, a strong convergence theorem of the proposed algorithm is proved under suitable conditions. As an application, we give a new strong convergence theorem for the split feasibility problem in Hilbert spaces. Finally, we give numerical results for split variational inclusion problems to demonstrate the efficiency of the proposed algorithm. [ABSTRACT FROM AUTHOR]

The purpose of the present paper is the numerical investigation of the interference phenomena between the waves generated by the individual hulls of a catamaran. The study focuses on the effects of both Froude number and demi-hull separation distance on resistance and on sinkage and trim. The numerical simulations are carried out by the URANS solver CFDShip-Iowa V.4 and, to assess the capability for prediction of resistance, sinkage and trim of the URANS code for twin-hull configuration vessels, a verification and validation study is performed for global as well as for local variables. A very good agreement between the numerical results and the experimental data is obtained, and the validation study demonstrates the high level of accuracy of the current predictions, which are used to have a better insight into the interference phenomena. In accordance with the experiments, within Fr = 0.45-0.65, the catamaran has a significantly higher resistance coefficient compared to the mono-hull; furthermore, the C value increases with decreasing the separation distance between the twin hulls. On the contrary, at Fr lower than 0.45 and at Fr higher than 0.65, the effects of hull spacing on resistance as well as on sinkage and trim can be neglected. The flow field characteristics, wave pattern, wave cuts and pressure distributions are analyzed through the CFD analysis. Finally, the effects of the Reynolds number on resistance are also investigated and results show a small decrease in interference with increasing the Reynolds number. [ABSTRACT FROM AUTHOR]

Given an uncountable cardinal $${\kappa}$$ that satisfies $${\kappa^{\kappa}=\kappa}$$ , we provide a forcing that is $${<\kappa}$$ -closed, has size $${2^\kappa}$$ and is $${\kappa^+}$$ -cc (and thus in particular preserves all cofinalities), to introduce a Σ-definable wellorder (with parameters) of $${{\rm H}({\kappa^+})}$$ . This improves (and also simplifies the proof of) the main result of Holy and Lücke (Fundam Math 226(3):221-236, ), where such a wellorder is introduced by a forcing which potentially collapses cardinals, and where the additional requirement that $${2^\kappa}$$ be regular is needed. As an application, we use this to infer that Σ-definable wellorderings (using parameters) of $${{\rm H}({\kappa^+})}$$ can be introduced for many different cardinals $${\kappa}$$ simultaneously, while preserving a lot of ground model structure, improving results of Friedman and Holy (Fundam Math 215(2):133-166, ) and Friedman and Lücke (Ann Pure Appl Logic, accepted). Moreover the results of this paper answer Holy and Lücke (, Questions 5.2 and 5.3). [ABSTRACT FROM AUTHOR]

Tutte conjectured that every 4-edge-connected graph admits a nowhere-zero 3-flow. In this paper, we show that this conjecture is true for Cayley graph on generalized dihedral groups and generalized quaternion groups, which generalizes the result of F. Yang and X. Li [Inform. Process. Lett., 2011, 111: 416-419]. We also generalizes an early result of M. Nánásiová and M. Škoviera [J. Algebraic Combin., 2009, 30: 103-110]. [ABSTRACT FROM AUTHOR]

The bondage number b( G) of a graph G is the cardinality of a minimum set of edges whose removal from G results in a graph with a domination number greater than that of G. In this paper, we obtain the exact value of the bondage number of the strong product of two paths. That is, for any two positive integers m ⩾ 2 and n ⩾ 2, b( P ⊠ P) = 7 − r( m) − r( n) if ( r( m), r( n)) = (1, 1) or (3, 3), 6 − r( m) − r( n) otherwise, where r( t) is a function of positive integer t, defined as r( t) = 1 if t ≡ 1 (mod 3), r( t) = 2 if t ≡ 2 (mod 3), and r( t) = 3 if t ≡ 0 (mod 3). [ABSTRACT FROM AUTHOR]

Let X be the vertex set of K. A k-cycle packing of K is a triple ( X, C, L), where C is a collection of edge disjoint k-cycles of K and L is the collection of edges of K not belonging to any of the k-cycles in C. A k-cycle packing ( X, C, L) is called resolvable if C can be partitioned into almost parallel classes. A resolvable maximum k-cycle packing of K, denoted by k-RMCP( n), is a resolvable k-cycle packing of K, ( X, C, L), in which the number of almost parallel classes is as large as possible. Let D( n, k) denote the number of almost parallel classes in a k-RMCP( n). D( n, k) for k = 3, 4 has been decided. When n ≡ k (mod 2 k) and k ≡ 1 (mod 2) or n ≡ 1 (mod 2 k) and k ∈ {6, 8, 10, 14} ∪ { m: 5 ⩽ m ⩽ 49, m ≡ 1 (mod 2)}, D( n, k) also has been decided with few possible exceptions. In this paper, we shall decide D( n, 5) for all values of n ⩾ 5. [ABSTRACT FROM AUTHOR]

Consider a data set of vector-valued observations that consists of noisy inliers, which are explained well by a low-dimensional subspace, along with some number of outliers. This work describes a convex optimization problem, called reaper, that can reliably fit a low-dimensional model to this type of data. This approach parameterizes linear subspaces using orthogonal projectors and uses a relaxation of the set of orthogonal projectors to reach the convex formulation. The paper provides an efficient algorithm for solving the reaper problem, and it documents numerical experiments that confirm that reaper can dependably find linear structure in synthetic and natural data. In addition, when the inliers lie near a low-dimensional subspace, there is a rigorous theory that describes when reaper can approximate this subspace. [ABSTRACT FROM AUTHOR]

Let H and X be subgroups of a group G. We say that a subgroup H is X-propermutable in G provided that there is a subgroup B of G such that G = N( H) B and H X-permutes (in the sense of [1]) with all subgroups of B. In this paper we analyze the influence of X-propermutable subgroups on the structure of a finite group G. In particular, it is proved that G is a soluble PST-group if and only if all Hall subgroups and all maximal subgroups of every Hall subgroup of G are X-propermutable in G, where X = Z( G). [ABSTRACT FROM AUTHOR]

This is an expository paper in which we present some simple observations on the stability of some inhomogeneous functional equations. In particular, we state several stability results for the inhomogeneous Cauchy equation and for the inhomogeneous forms of the Jensen and linear functional equations. [ABSTRACT FROM AUTHOR]

Emden-Fowler type equations of arbitrary order are considered. The paper contains asymptotic estimates of nonoscillating continuable and noncontinuable solutions of such equations. [ABSTRACT FROM AUTHOR]

In this paper, we form a method to calculate the probability generating function of the total progeny of multitype branching process. As examples, we calculate probability generating function of the total progeny of the multitype branching processes within random walk which could stay at its position and (2-1) random walk. Consequently, we could give the probability generating functions and the distributions of the first passage time of corresponding random walks. Especially, for recurrent random walk which could stay at its position with probability 0 < r < 1, we show that the tail probability of the first passage time decays as $\frac{2} {{\sqrt {\pi (1 - r)} }}\frac{1} {{\sqrt n }} $ when n → ∞. [ABSTRACT FROM AUTHOR]

The paper focuses on the degenerate Euler numbers, the degenerate Euler polynomials and the degenerate Bernoulli polynomials. By adopting the method of recurrences, two explicit expressions have been established for sums of products of the degenerate Euler polynomials and the degenerate Bernoulli polynomials. As a special case of the degenerate Euler polynomials, an expression can be obtained for... [ABSTRACT FROM AUTHOR]

This paper is concerned with a nonlocal reaction-diffusion equation with nonlocal source and interior absorption ut = ∫ RN J(x-y)(u(y,t) - u(x,t)) dy + λ ∫ Ω uq dx - up, x ∈Ω, t > 0, u(x,t) = 0,x ∉ Ω, t ≥ 0, u(x,0) = u0(x), x ∈ Ω. We investigate the critical extinction exponents for the problem based on some adequate supersolutions and subsolutions. [ABSTRACT FROM AUTHOR]

By combining Korpelevich's extragradient method, the viscosity approximation method, the hybrid steepest-descent method, Mann's iteration method, and the gradient-projection method with regularization, a hybrid multi-step extragradient algorithm with regularization for finding a solution of triple hierarchical variational inequality problem is introduced and analyzed. It is proven that under appropriate assumptions, the proposed algorithm converges strongly to a unique solution of a triple hierarchical variational inequality problem which is defined over the set of solutions of a hierarchical variational inequality problem defined over the set of common solutions of finitely many generalized mixed equilibrium problems (GMEP), finitely many variational inclusions, fixed point problems, and the split feasibility problem (SFP). We also prove the strong convergence of the proposed algorithm to a common solution of the SFP, finitely many GMEPs, finitely many variational inclusions, and the fixed point problem of a strict pseudocontraction. The results presented in this paper improve and extend the corresponding results announced by several others. [ABSTRACT FROM AUTHOR]

A matrix with zero diagonal is called a Euclidean distance matrix when the matrix values are measurements of distances between points in a Euclidean space. Because of data errors such a matrix may not be exactly Euclidean and it is desirable in many applications to find the best Euclidean matrix which approximates the non-Euclidean matrix. In this paper the problem is formulated as a smooth unconstrained minimization problem, for which rapid convergence can be obtained. Comparative numerical results are reported. [ABSTRACT FROM AUTHOR]

This paper deals with the existence of interpolating rational functions serving as Thiele continued fraction convergents and also presents the expression for the remainder for such rational interpolations. These problems are similar to multipoint Padé approximations. For the limit case, the expression for the remainder in diagonal Padé approximations at zero is obtained; also a sufficiently simple expression for the exact value of the remainder in the case of the function √1 + z is derived. [ABSTRACT FROM AUTHOR]

Refutation systems are formal systems for inferring the falsity of formulae. These systems can, in particular, be used to syntactically characterise logics. In this paper, we explore the close connection between refutation systems and admissible rules. We develop technical machinery to construct refutation systems, employing techniques from the study of admissible rules. Concretely, we provide a refutation system for the intermediate logics of bounded branching, known as the Gabbay-de Jongh logics. We show that this gives a characterisation of these logics in terms of their admissible rules. To illustrate the technique, we also provide a refutation system for Medvedev's logic. [ABSTRACT FROM AUTHOR]

In this paper, we construct a category of short exact sequences of vector bundles and prove that it is equivalent to the category of double vector bundles. Moreover, operations on double vector bundles can be transferred to operations on the corresponding short exact sequences. In particular, we study the duality theory of double vector bundles in term of the corresponding short exact sequences. Examples including the jet bundle and the Atiyah algebroid are discussed. [ABSTRACT FROM AUTHOR]

In this paper, we mainly study zeros and poles of the forward differences Δ f( z), where f( z) is a finite order meromorphic function with two Borel exceptional values. [ABSTRACT FROM AUTHOR]

Some new characterizations of nonnegative Hamiltonian operator matrices are given. Several necessary and sufficient conditions for an unbounded nonnegative Hamiltonian operator to be invertible are obtained, so that the main results in the previously published papers are corollaries of the new theorems. Most of all we want to stress the method of proof. It is based on the connections between Pauli operator matrices and nonnegative Hamiltonian matrices. [ABSTRACT FROM AUTHOR]

Mathematical analysis of large genomes is a problem of current interest motivated by the development of DNA sequencing methods. To date, human and some other genomes have been sequenced. Certain characteristics of a genetic code shared by all these genomes are numerically analyzed in this paper. Relying on the results, a new property of the genetic code for overlaps of six and three genes in a single DNA strand is formulated. The choice of three termination codons out of 64 possible genetic code triplets does not influence the cardinality of the sets of nucleotide chains admitting sextuple and triple overlaps of genes. [ABSTRACT FROM AUTHOR]

This article deals with the oscillation of a certain class of fourth-order delay differential equations. Some new oscillation criteria (including Hille- and Nehari-type criteria) are presented. The results obtained in the paper improve some results from [C. Zhang, T. Li, B. Sun, and E. Thandapani, Appl. Math. Lett., 24, 1618 (2011)]. Two examples are presented to illustrate our main results. [ABSTRACT FROM AUTHOR]

In this paper, we introduce a mixed general type of variational relation problems, and establish the existence theorem of solutions of mixed general types of variational relation problems. Moreover, we study the stability of a solution set of mixed general types of variational relation problems. We prove that most of mixed general types of variational relation problems (in the sense of Baire category) are essential and, for any mixed general type of variational relation problems, there exists at least one essential connected component of its solution set. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to introduce a new three step iteration scheme for approximation of fixed points of the nonexpansive mappings. We show that our iteration process is faster than all of the Picard, the Mann, the Agarwal et al., and the Abbas et al. iteration processes. We support our analytic proof by a numerical example in which we approximate the fixed point by a computer using Matlab program. We also prove some weak convergence and strong convergence theorems for the nonexpansive mappings. [ABSTRACT FROM AUTHOR]

In this paper we present a new embedding of a semigroups into a semiband (idempotent-generated semigroup) of depth 4 (every element is the product of 4 idempotents) using a semidirect product construction. Our embedding does not assume that S is a monoid (although it assumes a weaker condition) and works also for (non-monoid) regular semigroups. In fact, this semidirect product construction works particularly well if the semigroup is regular: we can choose the semiband to have depth 2. We shall see that many properties of S are preserved by this construction and we shall compare it to other known embeddings. [ABSTRACT FROM AUTHOR]

In this paper we propose a new numerical method for solving stochastic differential equations (SDEs). As an application of this method we propose an explicit numerical scheme for a super linear SDE for which the usual Euler scheme diverges. [ABSTRACT FROM AUTHOR]

We investigate a selective version of property ( a) and prove a number of results showing that, under certain set theoretical conditions, ( a) spaces and selectively ( a) spaces behave in a very similar way, at least for separable spaces. Several results regarding the presence of the referred selective version in spaces from almost disjoint families are established; in particular, we give a combinatorial characterization of such presence. Consistent set theoretical hypotheses implying equivalence between being ( a) and being selectively ( a) within the referred class are presented, as well as hypotheses implying non-equivalence. We also show that the Continuum Hypothesis is independent of the statement asserting the above mentioned equivalence. The paper finishes by presenting some notes and questions on the role of set theoretical assumptions in the subject. [ABSTRACT FROM AUTHOR]

The purpose of the present paper is to solve the pexiderized versions of functional equations investigated by B. Nyul and G. Nyul [2], raised by the connection between products of quaternions and products of three-dimensional vectors. [ABSTRACT FROM AUTHOR]

Compressed sensing ensures the accurate reconstruction of sparse signals from far fewer samples than required in the classical Shannon-Nyquist theorem. In this paper, a generalized hard thresholding pursuit (GHTP) algorithm is presented that can recover unknown vectors without the sparsity level information. We also analyze the convergence of the proposed algorithm. Numerical experiments are given for synthetic and real-world data to illustrate the validity and the good performance of the proposed algorithm. [ABSTRACT FROM AUTHOR]

This paper deals with designing H filters of reduced order for two dimensional (2-D) continuous systems described by Roesser models, with uncertain state space matrices. These filters are characterized in terms of linear matrix inequalities (LMI), to minimize a bound on the H noise attenuation, by using homogeneous polynomially parameter-dependent matrices of arbitrary degree. The methodology is also particularized for full order and zero order (static) filters, where more simple LMI conditions are derived. Numerical examples are presented to illustrate the proposed methodology. [ABSTRACT FROM AUTHOR]

In this paper, vector groups whose holomorphs are isomorphic are studied. In connection with the studied problem, the concepts of a semi-characteristic and Γ( G)-decomposition of a group are introduced. The properties of such decompositions are described. Isomorphism conditions of holomorphically isomorphic vector groups are found. [ABSTRACT FROM AUTHOR]

A subgroup A of an Abelian group G is called its absolute ideal if A is an ideal of any ring on G. An Abelian group is called an RAI-group if there exists a ring on it in which every ideal is absolute. The problem of describing RAI-groups was formulated by L. Fuchs (Problem 93). In this paper, absolute ideals of torsion Abelian groups and torsion Abelian RAI-groups are described. [ABSTRACT FROM AUTHOR]

In this paper, we study torsion groups containing proper fully invariant subgroups isomorphic to the group itself, the so-called IF-groups. We introduce the concept of an admissible sequence of Ulm-Kaplansky invariants for primary groups by use of which a description of IF-groups is obtained in some important classes of p-groups. [ABSTRACT FROM AUTHOR]

It is well known that it is difficult to explore underwater terrains using an autonomous underwater vehicle due to the varieties and complexities of underwater terrain elements. Since conventional underwater terrain coverage techniques are usually based on the assumption that the underwater surface is planar, they generate an unnecessary exploration path especially on steep sloped surfaces of ocean basins. This paper proposes a new type of coverage technique, the hybrid terrain coverage framework (HTCF), which considers various surface conditions in three-dimensional environments and generates an efficient exploration path for all environments. The HTCF incorporates a planar terrain coverage algorithm, a spiral path terrain coverage algorithm, and a hybrid decision module to recognize and select the most suitable technique depending on the sloped surface variations. Simulation results show that the proposed HTCF is more efficient than the conventional terrain coverage algorithm in terms of the energy consumption of the underwater vehicle. [ABSTRACT FROM AUTHOR]

In this paper the Acoustic Analogy is used to predict the underwater noise from a complete scaled ship model in a steady course. The numerical investigation is performed by coupling an incompressible RANS code, equipped with a level-set approach to account for the fundamental time evolution of the free surface, to a FWH-based hydroacoustic solver, here suitably designed to manage the huge set of data coming from a full-unsteady hydrodynamic simulation. The results reveal the overall limited contribution from the propeller thickness and loading noise components and the fundamental one from the nonlinear quadrupole sources. The comparison between the hydrodynamic and hydroacoustic solutions point out the noticeable scattering effects due to the hull surface, the possible influence of sound refractions at the free surface and, above all, the leading role played by the turbulent fluctuating component of the velocity field. Finally, by computing the pressure time histories at a prescribed set of virtual hydrophones and turning them into the frequency domain, the ship noise footprint in dB is traced out, thus showing how the Acoustic Analogy can be effectively used to analyze the ship hydroacoustic behavior, both in terms of amplitude and directivity. [ABSTRACT FROM AUTHOR]

This paper considers the Cauchy problem of solutions for a class of sixth order 1-D nonlinear wave equations at high initial energy level. By introducing a new stable set we derive the result that certain solutions with arbitrarily positive initial energy exist globally. [ABSTRACT FROM AUTHOR]

In this paper, we introduce the new notion of almost Ψ-Geraghty contractive mappings and investigate the existence of a best proximity point for such mappings in complete metric spaces via the weak P-property. We provide an example to validate our best proximity point theorem. The obtained results extend, generalize, and complement some known fixed and best proximity point results from the literature. [ABSTRACT FROM AUTHOR]

Very recently, the notion of a Ψ-Geraghty type contraction was defined by Gordji et al. (Fixed Point Theory and Applications 2012:74, 2012). In this short note, we realize that the main result via Ψ-Geraghty type contraction is equivalent to an existing related result in the literature. Consequently, all results inspired by the paper of Gordji et al. in (Fixed Point Theory and Applications 2012:74, 2012) can be derived in the same way. [ABSTRACT FROM AUTHOR]

In this paper, we use topological degree theory to establish new results on the existence of periodic solutions for a p-Laplacian neutral Rayleigh equation. [ABSTRACT FROM AUTHOR]

In this paper, we define some non-Riemannian curvature properties for Cartan spaces. We consider a Cartan space with the mth root metric. We prove that every mth root Cartan space of isotropic Landsberg curvature, or isotropic mean Landsberg curvature, or isotropic mean Berwald curvature reduces to a Landsberg, weakly Landsberg, and weakly Berwald spaces, respectively. Then we show that the mth root Cartan space of almost vanishing H-curvature satisfies H = 0. [ABSTRACT FROM AUTHOR]

In this paper, we consider topological (2 , 2)-transformation groups. [ABSTRACT FROM AUTHOR]

In this paper, we indicate several aspects of the notion of homotopy Gerstenhaber algebras and give some important examples and applications. [ABSTRACT FROM AUTHOR]

This paper is a survey of our recent results concerning metabelian varieties, and more specifically, varieties generated by wreath products of Abelian groups. We give a full classification of cases where sets of wreath products of Abelian groups $$ \mathfrak{X} $$ Wr $$ \mathfrak{Y} $$ = { X Wr Y | X ∈$$ \mathfrak{X} $$ , Y ∈ $$ \mathfrak{Y} $$ } and $$ \mathfrak{X} $$ wr $$ \mathfrak{Y} $$ = { X wr Y | X ∈ $$ \mathfrak{X} $$ , Y ∈ $$ \mathfrak{Y} $$ } generate the product variety $$ \mathfrak{X} $$ var ( $$ \mathfrak{Y} $$ ). [ABSTRACT FROM AUTHOR]

Let Ω be a set and TΩ be the set of all 5-ary functions over Ω. In this paper, by considering five Mann’s compositions on TΩ, we obtain a (2 , 5)-semigroup and an abstract characterization of this algebra. [ABSTRACT FROM AUTHOR]

In this paper, recently published results on matrix spectral factorization is reviewed, and their connection to wavelet matrices is revealed. [ABSTRACT FROM AUTHOR]

In this paper we consider a class of differential equations with state-dependent delays. We show first and second-order differentiability of the solution with respect to parameters in a pointwise sense and also using the $$C$$ C -norm on the state-space, assuming that the state-dependent time lag function is piecewise strictly monotone. [ABSTRACT FROM AUTHOR]

In this paper, we give some decompositions of triples of $\mathbb{Z}_{p^n } $ or $\mathbb{Z}_{3p^n } $ into cyclic triple systems. New constructions of difference families are given. Some infinite classes of simple cyclic triple systems are obtained from these decompositions. [ABSTRACT FROM AUTHOR]