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The nitty-gritty of this paper is to estimate the mean of the number of persons possessing a rare sensitive attribute by utilizing the Poisson distribution in stratified survey sampling. It is also shown that the proposed models are more efficient than Lee et al.’s (Statistics 47:575–589, 2013) models in both the cases when the proportion of persons possessing a rare unrelated attribute is known and that when it is unknown. Properties of the proposed randomized response models have been studied alongwith recommendations. Numerical illustrations are also given in support of the present study.

In this paper, we are interested to prove the uniform exponential decay of the energy for the finite difference fully-discretization of 1-D wave equation with an interior damping at $$\xi $$ . To this end, we decompose the fully discrete system into two subsystems: a conservative system, and a non conservative one. We show under a numerical hypothesis on $$\xi $$ that a uniform observability inequality holds for a conservative system, when the mesh size tends to zero using Fourier series technique. Then, we use the observability inequality to prove the uniform exponential decay of the energy for the damped system. Finally, we describe some numerical experiments to illustrate the exponential decay of the energy.

The main aim of this paper is to introduced the operations "Union" and "Intersection," and four operators $O_1, O_2, O_3, O_4 $ on interval-valued hesitant fuzzy soft sets and discuss some of their properties., Comment: 14 pages

In this paper, we introduce (weak) Stampacchia and Minty arcwise connected vector variational-like inequalities in the term of right upper-Dini-derivative and establish not only the relations of introduced inequalities with vector optimization problems but also the existence results, by using KKM-Fan theorem and Brouwer fixed point theorem. Examples are provided to illustrate the derived results.

In this paper, using t-norm T, the notion of (imaginable) T-fuzzy KU-ideals of KU-algebras are introduced and investigated their related results. Images and preimages of KU-ideals under homomorphism are investigated. Using level subsets of KU-algebras, some characterization theorems are given. The Cartesian product and T-product of T-fuzzy KU-ideals of KU-algebras are discussed.

Davvaz and Leoreanu-Fotea (Commun Algebra 38(10):3621–3636, 2010) studied binary relations on ternary semihypergroups. A ternary relation or triadic relation is a relation in which the number of places in the relation is three. Now, in this paper, instead of binary relations we consider ternary relations and instead of ternary semihypergroups we consider ordinary semihypergroups. Then, we study ternary relations on semihypergroups. In particular, we discuss some properties of compatible ternary relations on them.

In this paper, we introduce a new subclass of analytic and bi-univalent functions in the open unit disk $$\mathbb {U}$$ . For functions belonging to this class, we obtain initial coefficient bounds and Fekete–Szego inequality.

In this paper, we introduce the new concept isoclinism of two non-commuting graphs. We describe it with this hope to determine the properties of the graph with large number of vertices and edges more easier by use of its smaller correspondence graph in its isoclinic class. In 1939, Hekster classified the groups by n-isoclinism which was weaker than isomorphism, where n is a positive integer. The abelian groups are in the same class by group-isoclinism, although their intrinsic properties are not the same. The notion of isoclinic groups is the inspiration to define the isoclinism of two graphs. The isoclinism of two graphs is a pair of significant special isomorphism between the quotient graphs of the given graphs. We observe that all complete 3-partite non-commuting graphs are in the same isoclinic class and the non-commuting graph associated to the dihedral group of order 8, $$D_{8}$$ is the representative of this class.

In this paper, we introduce the notion of a central B-automorphism of a finite B-algebra. Also some properties of a finite B-algebra and B-automorphism algebra are investigated.

This paper deals the notion of interval valued instuitionistic fuzzy subalgebras of $$\beta $$ -algebra and investigate some of the related results.

In this paper we consider a class of impulsive neutral stochastic functional differential equations with variable delays driven simultaneously by a fractional Brownian motion and a Poisson point processes in a Hilbert space. We prove an existence and uniqueness result and we establish some conditions ensuring the exponential decay to zero in mean square for the mild solution by means of the Banach fixed point theory. Finally, an illustrative example is given to demonstrate the effectiveness of the obtained result.

In this paper we generalize the concept of commutator socle regular abelian $$p\hbox {-groups}$$ for the QTAG-modules. In fact this is an extension of the study of socle regular, strong socle regular and projection-invariant QTAG-modules (Sikander et al., New Trends Math Sci 2(2):129–133, 2014; Sci Ser A Math Sci 25:47–53, 2014; J Egypt Math Soc, 2015. Here we investigate commutator socle regular modules, study their crucial properties and establish their relationship with the above mentioned modules.

In the present paper, we study modified Szasz–Durrmeyer positive linear operators involving Charlier polynomials, one of the discrete orthogonal polynomials which are generalization of Szasz Durrmeyer operators. Also, King type modification of these operators is given. We obtain uniform convergence of our operators with the help of Korovkin theorem, asymptotic formula and the order of approximation by using classical modulus of continuity.

The purpose of this paper is to give some fixed point results for mappings involving generalized $$(\psi ,\varphi )$$ -contractions via rational expressions in the setup of partially ordered b-metric spaces. Our main results extend, generalize and enrich several well known comparable results in the recent literature. Moreover, some examples and an application to integral equation are given here to illustrate the usability of the obtained results.

In this paper, we obtain initial coefficient bounds for functions belong to a subclass of analytic bi-univalent functions related to pseudo-starlike functions by using the Chebyshev polynomials and also we find Fekete-Szego inequalities for this class.

In this paper, our main objective is to introduce and investigate the interval-valued (in short, (i-v)) prime fuzzy hyperideal in semihypergroups in detail. We notice that every (i-v) semiprime fuzzy hyperideal may not be an (i-v) prime fuzzy hyperideal and we produce a counter example to illustrate this result. Moreover, we define (i-v) fuzzy hyper radical of an (i-v) fuzzy hyperideal of a semihypergroup. Finally, we study some interesting properties regarding this radical.

A dominating set D of a connected graph $$G = (V, E)$$ is said to be bi-connected dominating set if the induced subgraphs of both $$\langle D \rangle $$ and $$\langle V-D \rangle $$ are connected. The bi-connected domination number $$\gamma _{bc}(G)$$ is the minimum cardinality of a bi-connected dominating set. A $$\gamma _{bc}$$ -set is a minimum bi-connected dominating set of G. In this paper, we obtain the Partially Balanced Incomplete Block (PBIB)-designs with m = 1, 2, 3, 4 and $$\lfloor \frac{p}{2}\rfloor $$ association schemes arising from $$\gamma _{bc}$$ -sets of some special classes of graphs.

The concept of a $$\Gamma $$ -semigroup has been introduced by Mridul Kanti Sen in the Int. Symp., New Delhi, 1981. It is well known that the Green’s relations play an essential role in studying the structure of semigroups. In the present paper we deal with an application of $$\Gamma $$ -semigroups techniques to the Green’s Theorem in an attempt to show the way we pass from semigroups to $$\Gamma $$ -semigroups.

In the present paper the Euler transform of the V-function is obtained. The main result provides useful extension and unification of a number of (known or new) results for various special cases of the V-function. For the sake of illustration, some special cases of the main result are mentioned.

The purpose of the present paper is to establish connections between various subclasses of analytic univalent functions by applying certain convolution operator involving Poisson distribution series. To be more precise,we investigate such connections with the classes of analytic univalent functions of $$\beta $$ -starlike and $$\beta $$ -uniformly convex functions of order $$\alpha $$ in the open unit disk $${\mathbb {U}}$$ . Further we point out some consequences of our main results.

In this paper we consider an M/G/1 queueing model with single working vacation and vacation interruption. By studying the spectral properties of the corresponding operator we obtain that the time-dependent solution of the model strongly converges to its steady-state solution.

In this paper we introduce modules over both left and right Hom-alternative algebras. We give some constructions of left and right Hom-alternative modules and give various properties of both, as well as examples. Then, we prove that morphisms of left alternative algebras extend to morphisms of left Hom-alternative algebras. Next, we introduce comodules over Hom–Poisson coalgebras and show that we may obtain a structure map of a comodule over a Hom–Poisson coalgebra from a given one.

In this paper we study separation axioms and connected properties on (semi)topological quotient BCK-algebras. We bring some conditions which under a (semi)topological quotient BCK-algebra have at least one of the topological properties $$T_1,$$ Hausdorff, regular, normal, connected, locally connected, totally disconnected space.

In this paper, we study some properties and behavior of finite Gorenstein FI-flat dimension through the methods of relative homological algebra.

In this paper, using a generalized translation operator, we obtain an analog of Younis’s Theorem 5.2 in Younis (Int J Math Math Sci 9:301–312, 1986) for the generalized Fourier-Bessel transform for functions satisfying the Fourier-Bessel Dini Lipschitz condition in the space $$L_{\alpha ,n}^{2}$$ .

Many studies have investigated lattices of fuzzy algebraic systems. One of them belongs to Borzooei et al. (Soft Comput 12:739–749, 2008) who found some properties of lattices of fuzzy algebraic structures. In this study, we solve the problem of finding necessary and sufficient conditions for distributivity and modularity of lattice of fuzzy hyperideals of a hyperring which was one of the open problems in Borzooei’s paper.

Recently the present author introduced the notion of generalized quasi-conformal curvature tensor which bridges conformal curvature tensor, concircular curvature tensor, projective curvature tensor and conharmonic curvature tensor. The object of the present paper is to find out curvature conditions for which Ricci solitons in Sasakian manifolds are sometimes shrinking and some other time remain expanding.

This paper is dealing with two split extensions of the form $$2^{8}{:}A_{9}.$$ We refer to these two groups by $$\overline{G}_{1}$$ and $$\overline{G}_{2}.$$ For $$\overline{G}_{1},$$ the 8-dimensional GF(2)-module is in fact the deleted permutation module for $$A_{9}.$$ We firstly determine the conjugacy classes of $$\overline{G}_{1}$$ and $$\overline{G}_{2}$$ using the coset analysis technique. The structures of inertia factor groups were determined for the two extensions. The inertia factor groups of $$\overline{G}_{1}$$ are $$A_{9},\,A_{8},\, S_{7},\,(A_{6} \times 3){:}2 $$ and $$(A_{5} \times A_{4}){:}2,$$ while the inertia factor groups of $$\overline{G}_{2}$$ are $$A_{9},\, PSL(2,8){:}3$$ and $$2^{3}{:}GL(3,2).$$ We then determine the Fischer matrices for these two groups and apply the Clifford–Fischer theory to compute the ordinary character tables of $$\overline{G}_{1}$$ and $$\overline{G}_{2}.$$ The Fischer matrices of $$\overline{G}_{1}$$ and $$\overline{G}_{2}$$ are all integer valued, with sizes ranging from 1 to 9 and from 1 to 4 respectively. The full character tables of $$\overline{G}_{1}$$ and $$\overline{G}_{2}$$ are $$84 \times 84$$ and $$40 \times 40$$ complex valued matrices respectively.

In this paper, we introduce the concepts of n-fold integral ideals and n-fold Boolean ideals in BL-algebras. With respect to concepts, we give some related results. In particular, we prove that an ideal is an n-fold integral ideal if and only if is an n-fold Boolean and (prime)maximal ideal. Also, we prove that a BL-algebra is an n-fold integral BL-algebra if and only if trivial ideal $$\{0\}$$ is an n-fold integral ideal. Moreover, we study relation between n-fold integral ideals and n-fold obstinate filters in BL-algebras by using the set of complement elements. Also, we describe relationship between n-fold Boolean ideals and n-fold positive implicative filters in BL-algebras.

The aim of this paper to establish the existence and uniqueness of coincidence and common fixed points of Nadler type set-valued mappings under various generalized contractive conditions in the context of ultrametric spaces. Illustrative examples are provided to support our results. As an application, we have obtained well-posedness of the common fixed point problems. The presented results generalize several existing results in the literature in ultrametric space setting.

In this paper, we give a characterization of the rough semiring \((T,\Delta ,\nabla )\). The order of a rough semiring is also derived. We present the idea of rough homomorphism on the set of all rough sets for the given information system together with the operations Praba \(\Delta \) and Praba \(\nabla \). We illustrate these concepts through examples.

This paper is devoted to GM-sets and their applications in Lie theory from the theoretical and computational points of view. We consider the GM-set of a transformation group G acting on a smooth manifold M as the set of all associated G-equivariant maps and then investigate the relation between the concepts of G-conjugacy and G-invariance in Lie theory with respect to the associated GM-set. We will also have a look at the fundamental and constructive concept of moving frames through the GM-sets and apply this construction to carry out a detailed survey of some basic concepts in Lie algebra theory.

To the best of our knowledge, till date there are only two directions along which fuzzy topology (general topology) can be compared, one is the generalization of fuzzy topology (such as fuzzy supra topology, generalized fuzzy topology etc.) and the other is the stronger form of fuzzy topology which is known as Alexandroff fuzzy topology. It means that a given topology is always linear. This paper aims to propose the third direction that is a new parallel form of fuzzy topology (or a non-linear topology) called fuzzy independent topology which is neither a generalization nor a stronger form of the given fuzzy topology though it is a unique natural offshoot of the given fuzzy topology but very rare in existence and that has been shown by defining fuzzy $$\gamma ^{*}$$ -open set in the sense of Dimitrije Andrijevic, by proving that fuzzy $$\gamma ^{*}$$ -open set and fuzzy open set are completely independent of each other though the collection of fuzzy $$\gamma ^{*}$$ -open sets are themselves a fuzzy topology therein. At the same time we claim that it is beyond the scope of general topology with the existing generalized open sets in literature and consequently we move one more step towards learning the difference between topology and fuzzy topology. To this end, we study the fundamental properties of the new structure. Also we study some of the basic properties and characterizations of fuzzy $$\gamma ^{*}$$ -open sets and few of their applications. The investigation enables us to present a new covering property of the given fuzzy topological space and the preservation theory is obtained. Finally to illustrate the advantage of the proposed concept, we compare the obtained results with some already existing ones.

In this paper, we introduce and study the concept of almost continuity in weak structures (Csaszar in Acta Math Hung 131(1–2):193–195, 2011) and discuss some of its characteristic properties. Finally, we give some applications of this new kind of continuity.

In this paper, the non-Hermitian positive definite linear systems are solved via preconditioned Krylov subspace methods such as the generalized minimal residual (GMRES) method. To do so, the two-parameter generalized Hermitian and skew-Hermitian splitting (TGHSS) iteration method is applied to establish an m-step polynomial preconditioner. Some theoretical results are also given to investigate the convergence properties of the preconditioned method. Three numerical examples are presented to demonstrate the performance of the new method and to compare it with a recently proposed method.

In this paper, we generalize the notion of soft connectedness (Chen, Some Local Properties of Soft Semi-Open Sets, 2013; Kandil et al., J New Results Sci 4:90–108, 2014; Lin, Int J Math Sci Eng 7(2):1–7, 2013) by using the notion of $$\beta $$ -open soft sets. Also, the concept of $$\beta $$ -irresolute soft functions is introduced, as a generalization of $$\beta $$ -continuous soft functions and several properties of it is investigated. Further, we introduce and study the notion of $$\beta $$ -connectedness and gave the basic definitions and theorems about it. Finally, we show that, the surjective $$\beta $$ -irresolute soft image of soft $$\beta $$ -connected space is also soft $$\beta $$ -connected. This study is a standard generalization of some notions in classical topological spaces to soft topological spaces.

In this paper, we obtain a Suzuki type unique common fixed point theorem by using C - condition with rational expressions in partial metric spaces. Also we give an example which supports our main theorem.

The study of Weyl’s theorem and properties has been extended from the class of hermitian operators to the class of hyponormal and Toeplitz operator and several other non-normal classes. However, so far, this study has been limited to the bounded operators. In this paper, we introduce the class of unbounded class-\(\mathcal {A}\) operators and study Weyl-type theorems and properties for this class under certain condition. Certain relations have been established between the isolated spectral points with the Weyl spectrum and the B-Weyl spectrum. Also, for bounded operators, some variants of the Weyl’s Theorem imply the others. In the case of unbounded class-\(\mathcal {A}\) operators, several of those variants of the Weyl’s theorem have been shown to be equivalent.

Let \(K=\mathbb {Q}(\sqrt{dm}, \sqrt{dn})\) be a biquadratic field. In this paper we give a new integral basis for \(\mathbb {Z}_{K}\), by applying to biquadratic fields a method of D. Chatelain, for building formel integral bases of n-quadratic fields’ ring of integers. We give some examples. We set the monogenesis problem’s equations, and find the same characterizations that we’ve found, when we had used other bases. We give also new expressions for the elements of monogenesis.

In the present paper, we introduce a certain subclass of analytic univalent functions which is defined in terms of a quasi-subordination and we obtain certain sharp bounds of the Fekete–Szego functional for functions belonging to this class. The results presented give improved versions for this and associated classes involving the subordination and majorization. Special cases of the main results are also mentioned briefly.

Let X be a Banach lattice and $$\chi ^{2}_{f}$$ be an double gai Orlicz sequence space associated to an Orlicz function with the $$\Delta _{2}$$ - condition. In this paper we define the Ces $$\grave{\mathbf{a }}$$ ro $$\chi ^{2}$$ sequence space Ces $$_{p}^{q}\left( \chi ^{2}_{f}\right) $$ generated by a Orlicz sequence space and exhibit some general properties of the spaces.

In this paper, we introduce the concept of (m, n)-ideals in a non-associative ordered structure called an ordered \(\mathcal {LA}\)-semigroup. We also study the (m, n)-regular class of an ordered \(\mathcal {LA}\)-semigroup in terms of (m, n)-ideals.

In this paper we introduce a new general class of multi-valued Lipschitz hemicontractive mappings. We then prove strong convergence theorems for finding a fixed point of the mapping using a new two steps averaged algorithm. The method used in the proof is new and enables us to systematically avoid so many strong assumptions in the contemporary literature. The theorems obtained generalize and improve many results in the literature.

The zero divisor graph of a partially ordered set (poset, briefly) $$(P, \le )$$ with the least element 0, which is denoted by $$G^*(P)$$ , is an undirected graph with vertex set $$P^*= P{\setminus } \{0\}$$ and, for two distinct vertices x and y, x is adjacent to y in $$G^*(P)$$ if and only if $$\{x,y\}^l=\{0\}$$ , where, for a subset S of P, $$S^l$$ is the set of all elements $$x\in P$$ with $$x\le s$$ , for all $$s\in S$$ . In this paper we completely characterize all posets P with projective zero divisor graphs $$G^*(P)$$ .

In this paper, we consider the $$D(\pm k)$$ -triple $$\{k\mp 1,k, 4k\mp 1\}$$ and we prove that, if k is not a perfect square then: This extends a work done by Fujita [13].

Let R be a prime ring of characteristic different from two with center Z(R). In the present paper we study the case when a generalized derivation F associated with a nonzero derivation d of R satisfies $$[F([x, y]_k), [x, y]_k]\in Z(R)$$ for all x, y in some appropriate subset of R, where k is a fixed positive integer. We obtain a description of the structure of R and information on the form of F in terms of the standard identity $$s_4$$ and the multiplication by the specific element from the extended centroid.

In this paper we study the homogenization of the Cauchy–Dirichlet initial boundary value problems for the Navier–Stokes type equations, on one hand in an open set \(\Omega \) of \(\mathbb {R}^{N}\), on the other hand in porous media \(\Omega ^{\varepsilon }\). In the second case, the equations are classical unstationary Navier–Stokes one, and the porous media are periodic.

In this paper, we consider the problem of planarity and outerplanarity of iterated line graphs of the zero divisor graphs for finite commutative rings. We give a full characterization of all zero divisor graphs with respect to their planarity and outerplanarity indexes.

The permanent is a matrix function introduced (independently) by Cauchy and Binet and a number of results have so far been proved. In this paper, we extend the concept of permanent into rhotrix and also present a way of finding the permanent of a rhotrix and also establish some results. Rhotrix is an object that lies in some way between \(n\times n\) dimensional matrices and \(( {2n-1})\times (2n-1)\) dimensional matrices.

In this paper, the linear and nonlinear Schlomilch’s integral equations and their generalized forms are studied. The Schlomilch’s integral equations are used for many ionospheric problems, atmospheric and terrestrial physics. The generalized fractional order of the Chebyshev orthogonal functions (GFCF) collocation method is used to handle many forms of Schlomilch’s integral equations. The GFCF method can be used in the applied physics, applied mathematics, and engineering applications. The reliability of the GFCF method is justified through illustrative examples.