Mathematics

15 pages, 1761 KiB

Open AccessArticle

The Velocity of PCL Fluid in Human Lungs with Beaver and Joseph Boundary Condition by Using Asymptotic Expansion Method

by Sudaporn Poopra and Kanognudge Wuttanachamsri

Mathematics 2019, 7(6), 567; https://doi.org/10.3390/math7060567 - 24 Jun 2019

Cited by 4 | Viewed by 3311

Humans breathe air into the respiratory system through the trachea, but with all the pollutants in our environment (both outside and inside), the air we breathe may not be clean. When that is so, the respiratory system secretes mucus to trap dirt that [...] Read more.

Humans breathe air into the respiratory system through the trachea, but with all the pollutants in our environment (both outside and inside), the air we breathe may not be clean. When that is so, the respiratory system secretes mucus to trap dirt that is inhaled through the nostrils. The respiratory tract contains hair-like structures in the epithelial tissue, called cilia: These wave back and forth to help expel particles of dust, dirt, mucus, and contaminants from the body. Cilia are found in this layer (a porous medium) and the fluid in this layer is called the periciliary layer (PCL). This study aims to determine the velocity of the PCL fluid flow in motile cilia. Usually, fluids move due to pressure changes, but in this study, the velocity of solids or of the cilia moves the PCL fluid. Stokes-Brinkman equations are used to determine the velocity of PCL fluid flow when cilia form an angle with the horizontal plane. The Beavers and Joseph boundary condition is applied in this study. The asymptotic expansion method is adapted in order to determine the velocity of PCL from the movement of the cilia. Full article

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14 pages, 265 KiB

Open AccessFeature PaperArticle

Fuzzy Positive Implicative Filters of Hoops Based on Fuzzy Points

by Rajab Ali Borzooei, Mona Aaly Kologani, Mahdi Sabet Kish and Young Bae Jun

Mathematics 2019, 7(6), 566; https://doi.org/10.3390/math7060566 - 24 Jun 2019

Cited by 6 | Viewed by 2511

Abstract

In this paper, we introduce the notions of

(\in, \in)

-fuzzy positive implicative filters and

(\in, \in \lor q)

-fuzzy positive implicative filters in hoops and investigate their properties. We also define some equivalent definitions of them, [...] Read more.

In this paper, we introduce the notions of

(\in, \in)

-fuzzy positive implicative filters and

(\in, \in \lor q)

-fuzzy positive implicative filters in hoops and investigate their properties. We also define some equivalent definitions of them, and then we use the congruence relation on hoop defined in blue[Aaly Kologani, M.; Mohseni Takallo, M.; Kim, H.S. Fuzzy filters of hoops based on fuzzy points. Mathematics. 2019, 7, 430; doi:10.3390/math7050430] by using an

(\in, \in)

-fuzzy filter in hoop. We show that the quotient structure of this relation is a Brouwerian semilattice. Full article

(This article belongs to the Special Issue Fuzziness and Mathematical Logic )

2 pages, 169 KiB

Open AccessCorrection

Correction: Ali, M., et al. Study on the Development of Neutrosophic Triplet Ring and Neutrosophic Triplet Field. Mathematics 2018, 6, 46

by Yılmaz Çeven and Florentin Smarandache

Mathematics 2019, 7(6), 565; https://doi.org/10.3390/math7060565 - 24 Jun 2019

Cited by 1 | Viewed by 2230

Abstract

We have found the following errors in the article which was recently published in Mathematics [...] Full article

20 pages, 356 KiB

Open AccessArticle

An Introduction to Space–Time Exterior Calculus

by Ivano Colombaro, Josep Font-Segura and Alfonso Martinez

Mathematics 2019, 7(6), 564; https://doi.org/10.3390/math7060564 - 21 Jun 2019

Cited by 7 | Viewed by 4262

Abstract

The basic concepts of exterior calculus for space–time multivectors are presented: Interior and exterior products, interior and exterior derivatives, oriented integrals over hypersurfaces, circulation and flux of multivector fields. Two Stokes theorems relating the exterior and interior derivatives with circulation and flux, respectively, [...] Read more.

The basic concepts of exterior calculus for space–time multivectors are presented: Interior and exterior products, interior and exterior derivatives, oriented integrals over hypersurfaces, circulation and flux of multivector fields. Two Stokes theorems relating the exterior and interior derivatives with circulation and flux, respectively, are derived. As an application, it is shown how the exterior-calculus space–time formulation of the electromagnetic Maxwell equations and Lorentz force recovers the standard vector-calculus formulations, in both differential and integral forms. Full article

(This article belongs to the Special Issue Advanced Mathematical Methods: Theory and Applications)

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9 pages, 731 KiB

Open AccessArticle

Neutrosophic Triplets in Neutrosophic Rings

by Vasantha Kandasamy W. B., Ilanthenral Kandasamy and Florentin Smarandache

Mathematics 2019, 7(6), 563; https://doi.org/10.3390/math7060563 - 20 Jun 2019

Cited by 14 | Viewed by 2721

Abstract

The neutrosophic triplets in neutrosophic rings

⟨ Q \cup I ⟩

and

⟨ R \cup I ⟩

are investigated in this paper. However, non-trivial neutrosophic triplets are not found in

⟨ Z \cup I ⟩

. In the neutrosophic ring of integers [...] Read more.

The neutrosophic triplets in neutrosophic rings

⟨ Q \cup I ⟩

and

⟨ R \cup I ⟩

are investigated in this paper. However, non-trivial neutrosophic triplets are not found in

⟨ Z \cup I ⟩

. In the neutrosophic ring of integers

Z \ {0, 1}

, no element has inverse in Z. It is proved that these rings can contain only three types of neutrosophic triplets, these collections are distinct, and these collections form a torsion free abelian group as triplets under component wise product. However, these collections are not even closed under component wise addition. Full article

(This article belongs to the Special Issue New Challenges in Neutrosophic Theory and Applications)

26 pages, 6965 KiB

Open AccessArticle

A Generic Family of Optimal Sixteenth-Order Multiple-Root Finders and Their Dynamics Underlying Purely Imaginary Extraneous Fixed Points

by Min-Young Lee, Young Ik Kim and Beny Neta

Mathematics 2019, 7(6), 562; https://doi.org/10.3390/math7060562 - 20 Jun 2019

Cited by 3 | Viewed by 2907

Abstract

A generic family of optimal sixteenth-order multiple-root finders are theoretically developed from general settings of weight functions under the known multiplicity. Special cases of rational weight functions are considered and relevant coefficient relations are derived in such a way that all the extraneous [...] Read more.

A generic family of optimal sixteenth-order multiple-root finders are theoretically developed from general settings of weight functions under the known multiplicity. Special cases of rational weight functions are considered and relevant coefficient relations are derived in such a way that all the extraneous fixed points are purely imaginary. A number of schemes are constructed based on the selection of desired free parameters among the coefficient relations. Numerical and dynamical aspects on the convergence of such schemes are explored with tabulated computational results and illustrated attractor basins. Overall conclusion is drawn along with future work on a different family of optimal root-finders. Full article

(This article belongs to the Special Issue Iterative Methods for Solving Nonlinear Equations and Systems)

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22 pages, 2807 KiB

Open AccessArticle

Shift Scheduling with the Goal Programming Method: A Case Study in the Glass Industry

by Özlem Kaçmaz, Haci Mehmet Alakaş and Tamer Eren

Mathematics 2019, 7(6), 561; https://doi.org/10.3390/math7060561 - 20 Jun 2019

Cited by 9 | Viewed by 4383

Abstract

Nowadays, resource utilization and management are very important for businesses. They try to make a profit by providing high levels of efficiency from available sources. Their labor force is one of these sources. Therefore, scheduling based on personnel satisfaction has become an important [...] Read more.

Nowadays, resource utilization and management are very important for businesses. They try to make a profit by providing high levels of efficiency from available sources. Their labor force is one of these sources. Therefore, scheduling based on personnel satisfaction has become an important problem in recent years. In this study, a case study was carried out in a glass factory in Ankara which has 7 department and 80 personnel. The aim of the study is to provide better service by distributing personnel to shifts in a fair and balanced manner. Assignment points are different for the departments where the personnel will work. Every personnel member is assigned to the department as best as possible. A goal programming method was used, and the results were better than those obtained using other methods. Full article

(This article belongs to the Special Issue Mathematical Methods in Applied Sciences)

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22 pages, 337 KiB

Open AccessArticle

The Modified Inertial Iterative Algorithm for Solving Split Variational Inclusion Problem for Multi-Valued Quasi Nonexpansive Mappings with Some Applications

by Pawicha Phairatchatniyom, Poom Kumam, Yeol Je Cho, Wachirapong Jirakitpuwapat and Kanokwan Sitthithakerngkiet

Mathematics 2019, 7(6), 560; https://doi.org/10.3390/math7060560 - 19 Jun 2019

Cited by 5 | Viewed by 3631

Abstract

Based on the very recent work by Shehu and Agbebaku in Comput. Appl. Math. 2017, we introduce an extension of their iterative algorithm by combining it with inertial extrapolation for solving split inclusion problems and fixed point problems. Under suitable conditions, we prove [...] Read more.

Based on the very recent work by Shehu and Agbebaku in Comput. Appl. Math. 2017, we introduce an extension of their iterative algorithm by combining it with inertial extrapolation for solving split inclusion problems and fixed point problems. Under suitable conditions, we prove that the proposed algorithm converges strongly to common elements of the solution set of the split inclusion problems and fixed point problems. Full article

(This article belongs to the Special Issue Iterative Methods for Solving Nonlinear Equations and Systems)

16 pages, 545 KiB

Open AccessArticle

Anti-Synchronization of a Class of Chaotic Systems with Application to Lorenz System: A Unified Analysis of the Integer Order and Fractional Order

by Liang Chen, Chengdai Huang, Haidong Liu and Yonghui Xia

Mathematics 2019, 7(6), 559; https://doi.org/10.3390/math7060559 - 19 Jun 2019

Cited by 10 | Viewed by 3084

Abstract

The paper proves a unified analysis for finite-time anti-synchronization of a class of integer-order and fractional-order chaotic systems. We establish an effective controller to ensure that the chaotic system with unknown parameters achieves anti-synchronization in finite time under our controller. Then, we apply [...] Read more.

The paper proves a unified analysis for finite-time anti-synchronization of a class of integer-order and fractional-order chaotic systems. We establish an effective controller to ensure that the chaotic system with unknown parameters achieves anti-synchronization in finite time under our controller. Then, we apply our results to the integer-order and fractional-order Lorenz system, respectively. Finally, numerical simulations are presented to show the feasibility of the proposed control scheme. At the same time, through the numerical simulation results, it is show that for the Lorenz chaotic system, when the order is greater, the more quickly is anti-synchronization achieved. Full article

(This article belongs to the Special Issue Impulsive Control Systems and Complexity)

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18 pages, 366 KiB

Open AccessArticle

Recursive Algorithms for Multivariable Output-Error-Like ARMA Systems

by Hao Ma, Jian Pan, Lei Lv, Guanghui Xu, Feng Ding, Ahmed Alsaedi and Tasawar Hayat

Mathematics 2019, 7(6), 558; https://doi.org/10.3390/math7060558 - 19 Jun 2019

Cited by 43 | Viewed by 3541

Abstract

This paper studies the parameter identification problems for multivariable output-error-like systems with colored noises. Based on the hierarchical identification principle, the original system is decomposed into several subsystems. However, each subsystem contains the same parameter vector, which leads to redundant computation. By taking [...] Read more.

This paper studies the parameter identification problems for multivariable output-error-like systems with colored noises. Based on the hierarchical identification principle, the original system is decomposed into several subsystems. However, each subsystem contains the same parameter vector, which leads to redundant computation. By taking the average of the parameter estimation vectors of each subsystem, a partially-coupled subsystem recursive generalized extended least squares (PC-S-RGELS) algorithm is presented to cut down the redundant parameter estimates. Furthermore, a partially-coupled recursive generalized extended least squares (PC-RGELS) algorithm is presented to further reduce the computational cost and the redundant estimates by using the coupling identification concept. Finally, an example indicates the effectiveness of the derived algorithms. Full article

(This article belongs to the Section Engineering Mathematics)

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8 pages, 263 KiB

Open AccessArticle

Characterization of Graphs Associated with Numerical Semigroups

by Muhammad Ahsan Binyamin, Hafiz Muhammad Afzal Siddiqui, Nida Munawar Khan, Adnan Aslam and Yongsheng Rao

Mathematics 2019, 7(6), 557; https://doi.org/10.3390/math7060557 - 19 Jun 2019

Cited by 7 | Viewed by 2930

Abstract

Let

Γ

be a numerical semigroup. We associate an undirected graph

G (Γ)

with a numerical semigroup

Γ

with vertex set

{v_{i} : i \in N \ Γ}

and edge set [...] Read more.

Let

Γ

be a numerical semigroup. We associate an undirected graph

G (Γ)

with a numerical semigroup

Γ

with vertex set

{v_{i} : i \in N \ Γ}

and edge set

{v_{i} v_{j} \Leftrightarrow i + j \in Γ}

. In this article, we discuss the connectedness, diameter, girth, and some other related properties of the graph

G (Γ)

. Full article

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18 pages, 805 KiB

Open AccessArticle

Extending Structures for Lie 2-Algebras

by Yan Tan and Zhixiang Wu

Mathematics 2019, 7(6), 556; https://doi.org/10.3390/math7060556 - 18 Jun 2019

Cited by 1 | Viewed by 2476

Abstract

The extending structures problem for strict Lie 2-algebras is studied. To provide the theoretical answer to this problem, this paper introduces the unified product of a given strict Lie 2-algebra

g

and 2-vector space V. The unified product includes some interesting products [...] Read more.

The extending structures problem for strict Lie 2-algebras is studied. To provide the theoretical answer to this problem, this paper introduces the unified product of a given strict Lie 2-algebra

g

and 2-vector space V. The unified product includes some interesting products such as semi-direct product, crossed product, and bicrossed product. The paper focuses on crossed and bicrossed products, which give the answer to the extension problem and factorization problem, respectively. Full article

(This article belongs to the Special Issue General Algebraic Structures)

19 pages, 988 KiB

Open AccessFeature PaperArticle

Restricted Gompertz-Type Diffusion Processes with Periodic Regulation Functions

by Virginia Giorno and Amelia G. Nobile

Mathematics 2019, 7(6), 555; https://doi.org/10.3390/math7060555 - 18 Jun 2019

Cited by 10 | Viewed by 3190

Abstract

We consider two different time-inhomogeneous diffusion processes useful to model the evolution of a population in a random environment. The first is a Gompertz-type diffusion process with time-dependent growth intensity, carrying capacity and noise intensity, whose conditional median coincides with the deterministic solution. [...] Read more.

We consider two different time-inhomogeneous diffusion processes useful to model the evolution of a population in a random environment. The first is a Gompertz-type diffusion process with time-dependent growth intensity, carrying capacity and noise intensity, whose conditional median coincides with the deterministic solution. The second is a shifted-restricted Gompertz-type diffusion process with a reflecting condition in zero state and with time-dependent regulation functions. For both processes, we analyze the transient and the asymptotic behavior of the transition probability density functions and their conditional moments. Particular attention is dedicated to the first-passage time, by deriving some closed form for its density through special boundaries. Finally, special cases of periodic regulation functions are discussed. Full article

(This article belongs to the Special Issue Diffusion Processes Associated with Growth Curves: Probabilistic and Inferential Analysis)

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50 pages, 2766 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Rules for Fractional-Dynamic Generalizations: Difficulties of Constructing Fractional Dynamic Models

by Vasily E. Tarasov

Mathematics 2019, 7(6), 554; https://doi.org/10.3390/math7060554 - 18 Jun 2019

Cited by 34 | Viewed by 4477

Abstract

This article is a review of problems and difficulties arising in the construction of fractional-dynamic analogs of standard models by using fractional calculus. These fractional generalizations allow us to take into account the effects of memory and non-locality, distributed lag, and scaling. We [...] Read more.

This article is a review of problems and difficulties arising in the construction of fractional-dynamic analogs of standard models by using fractional calculus. These fractional generalizations allow us to take into account the effects of memory and non-locality, distributed lag, and scaling. We formulate rules (principles) for constructing fractional generalizations of standard models, which were described by differential equations of integer order. Important requirements to building fractional generalization of dynamical models (the rules for “fractional-dynamic generalizers”) are represented as the derivability principle, the multiplicity principle, the solvability and correspondence principles, and the interpretability principle. The characteristic properties of fractional derivatives of non-integer order are the violation of standard rules and properties that are fulfilled for derivatives of integer order. These non-standard mathematical properties allow us to describe non-standard processes and phenomena associated with non-locality and memory. However, these non-standard properties lead to restrictions in the sequential and self-consistent construction of fractional generalizations of standard models. In this article, we give examples of problems arising due to the non-standard properties of fractional derivatives in construction of fractional generalizations of standard dynamic models in economics. Full article

(This article belongs to the Special Issue Mathematical Economics: Application of Fractional Calculus)

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9 pages, 287 KiB

Open AccessArticle

How to Obtain Global Convergence Domains via Newton’s Method for Nonlinear Integral Equations

by José Antonio Ezquerro and Miguel Ángel Hernández-Verón

Mathematics 2019, 7(6), 553; https://doi.org/10.3390/math7060553 - 17 Jun 2019

Cited by 8 | Viewed by 3075

Abstract

We use the theoretical significance of Newton’s method to draw conclusions about the existence and uniqueness of solution of a particular type of nonlinear integral equations of Fredholm. In addition, we obtain a domain of global convergence for Newton’s method. Full article

(This article belongs to the Special Issue Iterative Methods for Solving Nonlinear Equations and Systems)

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15 pages, 289 KiB

Open AccessArticle

Generalizations of Several Inequalities Related to Multivariate Geometric Means

by Bo-Yan Xi, Ying Wu, Huan-Nan Shi and Feng Qi

Mathematics 2019, 7(6), 552; https://doi.org/10.3390/math7060552 - 17 Jun 2019

Cited by 5 | Viewed by 4033

Abstract

In the paper, by some methods in the theory of majorization, the authors generalize several inequalities related to multivariate geometric means. Full article

20 pages, 313 KiB

Open AccessArticle

A Study of Regular and Irregular Neutrosophic Graphs with Real Life Applications

by Liangsong Huang, Yu Hu, Yuxia Li, P. K. Kishore Kumar, Dipak Koley and Arindam Dey

Mathematics 2019, 7(6), 551; https://doi.org/10.3390/math7060551 - 17 Jun 2019

Cited by 22 | Viewed by 4431

Abstract

Fuzzy graph theory is a useful and well-known tool to model and solve many real-life optimization problems. Since real-life problems are often uncertain due to inconsistent and indeterminate information, it is very hard for an expert to model those problems using a fuzzy [...] Read more.

Fuzzy graph theory is a useful and well-known tool to model and solve many real-life optimization problems. Since real-life problems are often uncertain due to inconsistent and indeterminate information, it is very hard for an expert to model those problems using a fuzzy graph. A neutrosophic graph can deal with the uncertainty associated with the inconsistent and indeterminate information of any real-world problem, where fuzzy graphs may fail to reveal satisfactory results. The concepts of the regularity and degree of a node play a significant role in both the theory and application of graph theory in the neutrosophic environment. In this work, we describe the utility of the regular neutrosophic graph and bipartite neutrosophic graph to model an assignment problem, a road transport network, and a social network. For this purpose, we introduce the definitions of the regular neutrosophic graph, star neutrosophic graph, regular complete neutrosophic graph, complete bipartite neutrosophic graph, and regular strong neutrosophic graph. We define the

d_{m}

- and

t d_{m}

-degrees of a node in a regular neutrosophic graph. Depending on the degree of the node, this paper classifies the regularity of a neutrosophic graph into three types, namely

d_{m}

-regular,

t d_{m}

-regular, and m-highly irregular neutrosophic graphs. We present some theorems and properties of those regular neutrosophic graphs. The concept of an m-highly irregular neutrosophic graph on cycle and path graphs is also investigated in this paper. The definition of busy and free nodes in a regular neutrosophic graph is presented here. We introduce the idea of the

μ

-complement and h-morphism of a regular neutrosophic graph. Some properties of complement and isomorphic regular neutrosophic graphs are presented here. Full article

(This article belongs to the Special Issue Graph-Theoretic Problems and Their New Applications)

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13 pages, 1811 KiB

Open AccessArticle

Numeric-Analytic Solutions for Nonlinear Oscillators via the Modified Multi-Stage Decomposition Method

by Emad A. Az-Zo’bi, Kamel Al-Khaled and Amer Darweesh

Mathematics 2019, 7(6), 550; https://doi.org/10.3390/math7060550 - 17 Jun 2019

Cited by 31 | Viewed by 3348

Abstract

This work deals with a new modified version of the Adomian-Rach decomposition method (MDM). The MDM is based on combining a series solution and decomposition method for solving nonlinear differential equations with Adomian polynomials for nonlinearities. With application to a class of nonlinear [...] Read more.

This work deals with a new modified version of the Adomian-Rach decomposition method (MDM). The MDM is based on combining a series solution and decomposition method for solving nonlinear differential equations with Adomian polynomials for nonlinearities. With application to a class of nonlinear oscillators known as the Lienard-type equations, convergence and error analysis are discussed. Several physical problems modeled by Lienard-type equations are considered to illustrate the effectiveness, performance and reliability of the method. In comparison to the 4th Runge-Kutta method (RK4), highly accurate solutions on a large domain are obtained. Full article

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12 pages, 763 KiB

Open AccessArticle

Distance Measures between the Interval-Valued Complex Fuzzy Sets

by Songsong Dai, Lvqing Bi and Bo Hu

Mathematics 2019, 7(6), 549; https://doi.org/10.3390/math7060549 - 16 Jun 2019

Cited by 54 | Viewed by 4391

Abstract

Complex fuzzy set (CFS) is a recent development in the field of fuzzy set (FS) theory. The significance of CFS lies in the fact that CFS assigned membership grades from a unit circle in the complex plane, i.e., in the form of a [...] Read more.

Complex fuzzy set (CFS) is a recent development in the field of fuzzy set (FS) theory. The significance of CFS lies in the fact that CFS assigned membership grades from a unit circle in the complex plane, i.e., in the form of a complex number whose amplitude term belongs to a

[0, 1]

interval. The interval-valued complex fuzzy set (IVCFS) is one of the extensions of the CFS in which the amplitude term is extended from the real numbers to the interval-valued numbers. The novelty of IVCFS lies in its larger range comparative to CFS. We often use fuzzy distance measures to solve some problems in our daily life. Hence, this paper develops some series of distance measures between IVCFSs by using Hamming and Euclidean metrics. The boundaries of these distance measures for IVCFSs are obtained. Finally, we study two geometric properties include rotational invariance and reflectional invariance of these distance measures. Full article

(This article belongs to the Special Issue Fuzzy Sets, Fuzzy Logic and Their Applications)

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18 pages, 1268 KiB

Open AccessArticle

Some Classes of Harmonic Mapping with a Symmetric Conjecture Point Defined by Subordination

by Lina Ma, Shuhai Li and Xiaomeng Niu

Mathematics 2019, 7(6), 548; https://doi.org/10.3390/math7060548 - 16 Jun 2019

Cited by 2 | Viewed by 2819

Abstract

In the paper, we introduce some subclasses of harmonic mapping, the analytic part of which is related to general starlike (or convex) functions with a symmetric conjecture point defined by subordination. Using the conditions satisfied by the analytic part, we obtain the integral [...] Read more.

In the paper, we introduce some subclasses of harmonic mapping, the analytic part of which is related to general starlike (or convex) functions with a symmetric conjecture point defined by subordination. Using the conditions satisfied by the analytic part, we obtain the integral expressions, the coefficient estimates, distortion estimates and the growth estimates of the co-analytic part g, and Jacobian estimates, the growth estimates and covering theorem of the harmonic function f. Through the above research, the geometric properties of the classes are obtained. In particular, we draw figures of extremum functions to better reflect the geometric properties of the classes. For the first time, we introduce and obtain the properties of harmonic univalent functions with respect to symmetric conjugate points. The conclusion of this paper extends the original research. Full article

(This article belongs to the Special Issue Mathematical Analysis and Analytic Number Theory 2019)

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12 pages, 271 KiB

Open AccessArticle

Generalized Geodesic Convexity on Riemannian Manifolds

by Izhar Ahmad, Meraj Ali Khan and Amira A. Ishan

Mathematics 2019, 7(6), 547; https://doi.org/10.3390/math7060547 - 16 Jun 2019

Cited by 4 | Viewed by 2795

Abstract

We introduce log-preinvex and log-invex functions on a Riemannian manifold. Some properties and relationships of these functions are discussed. A characterization for the existence of a global minimum point of a mathematical programming problem is presented. Moreover, a mean value inequality under geodesic [...] Read more.

We introduce log-preinvex and log-invex functions on a Riemannian manifold. Some properties and relationships of these functions are discussed. A characterization for the existence of a global minimum point of a mathematical programming problem is presented. Moreover, a mean value inequality under geodesic log-preinvexity is extended to Cartan-Hadamard manifolds. Full article

(This article belongs to the Special Issue Nonlinear and Convex Analysis)

6 pages, 333 KiB

Open AccessArticle

Reliability Analysis of the Bijective Connection Networks for Components

by Litao Guo and Chia-Wei Lee

Mathematics 2019, 7(6), 546; https://doi.org/10.3390/math7060546 - 14 Jun 2019

Cited by 9 | Viewed by 2512

Abstract

Connectivity is a critical parameter that can measure the reliability of networks. Let

Q \subseteq V (G)

be a vertex set. If

G - Q

is disconnected and every component of

G - Q

contains at least

k + 1

vertices, [...] Read more.

Connectivity is a critical parameter that can measure the reliability of networks. Let

Q \subseteq V (G)

be a vertex set. If

G - Q

is disconnected and every component of

G - Q

contains at least

k + 1

vertices, then Q is an extra-cut. The number of vertices in the smallest extra-cut is the extraconnectivity

κ_{k} (G)

. Suppose

ω (G)

is the number of components of G and

W \subseteq V (G)

; if

ω (G - W) \geq t

, then w is a t-component cut of G. The number of vertices in the least t-component cut is the t-component connectivity

c κ_{t} (G)

of G. The t-component edge connectivity

c λ_{t} (G)

is defined similarly. In this note, we study the BC networks and obtain the t-component (edge) connectivity of bijective connection networks for some t. Full article

(This article belongs to the Section Mathematics and Computer Science)

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12 pages, 288 KiB

Open AccessArticle

A New Algorithm for Fractional Riccati Type Differential Equations by Using Haar Wavelet

by M. Motawi Khashan, Rohul Amin and Muhammed I. Syam

Mathematics 2019, 7(6), 545; https://doi.org/10.3390/math7060545 - 14 Jun 2019

Cited by 21 | Viewed by 3534

Abstract

In this paper, a new collocation method based on Haar wavelet is developed for numerical solution of Riccati type differential equations with non-integer order. The fractional derivatives are considered in the Caputo sense. The method is applied to one test problem. The maximum [...] Read more.

In this paper, a new collocation method based on Haar wavelet is developed for numerical solution of Riccati type differential equations with non-integer order. The fractional derivatives are considered in the Caputo sense. The method is applied to one test problem. The maximum absolute estimated error functions are calculated, and the performance of the process is demonstrated by calculating the maximum absolute estimated error functions for a distinct number of nodal points. The results show that the method is applicable and efficient. Full article

(This article belongs to the Special Issue Advances in Differential and Difference Equations with Applications 2019)

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24 pages, 785 KiB

Open AccessFeature PaperArticle

Solutions of Direct and Inverse Even-Order Sturm-Liouville Problems Using Magnus Expansion

by Upeksha Perera and Christine Böckmann

Mathematics 2019, 7(6), 544; https://doi.org/10.3390/math7060544 - 14 Jun 2019

Cited by 9 | Viewed by 3663

Abstract

In this paper Lie group method in combination with Magnus expansion is utilized to develop a universal method applicable to solving a Sturm–Liouville problem (SLP) of any order with arbitrary boundary conditions. It is shown that the method has ability to solve direct [...] Read more.

In this paper Lie group method in combination with Magnus expansion is utilized to develop a universal method applicable to solving a Sturm–Liouville problem (SLP) of any order with arbitrary boundary conditions. It is shown that the method has ability to solve direct regular (and some singular) SLPs of even orders (tested for up to eight), with a mix of (including non-separable and finite singular endpoints) boundary conditions, accurately and efficiently. The present technique is successfully applied to overcome the difficulties in finding suitable sets of eigenvalues so that the inverse SLP problem can be effectively solved. The inverse SLP algorithm proposed by Barcilon (1974) is utilized in combination with the Magnus method so that a direct SLP of any (even) order and an inverse SLP of order two can be solved effectively. Full article

(This article belongs to the Special Issue Numerical Analysis: Inverse Problems – Theory and Applications)

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8 pages, 1485 KiB

Open AccessArticle

Study on Non-Commutativity Measure of Quantum Discord

by Jin Liang and Chengwei Zhang

Mathematics 2019, 7(6), 543; https://doi.org/10.3390/math7060543 - 14 Jun 2019

Cited by 4 | Viewed by 2680

Abstract

In this paper, we are concerned with the non-commutativity measure of quantum discord. We first present an explicit expression of the non-commutativity measure of quantum discord in the two-qubit case. Then we compare the geometric quantum discords for two dynamic models with their [...] Read more.

In this paper, we are concerned with the non-commutativity measure of quantum discord. We first present an explicit expression of the non-commutativity measure of quantum discord in the two-qubit case. Then we compare the geometric quantum discords for two dynamic models with their non-commutativity measure of quantum discords. Furthermore, we show that the results conducted by the non-commutativity measure of quantum discord are different from those conducted by both or one of the Hilbert-Schmidt distance discord and trace distance discord. These intrinsic differences indicate that the non-commutativity measure of quantum discord is incompatible with at least one of the well-known geometric quantum discords in the quantitative and qualitative representation of quantum correlations. Full article

(This article belongs to the Special Issue Mathematical Physics II)

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15 pages, 278 KiB

Open AccessArticle

Basic Fuzzy Event Space and Probability Distribution of Probability Fuzzy Space

by Guixiang Wang, Yifeng Xu and Sen Qin

Mathematics 2019, 7(6), 542; https://doi.org/10.3390/math7060542 - 14 Jun 2019

Cited by 8 | Viewed by 2601

Abstract

In this paper, the problems of basic fuzzy event space and of probability fuzzy space are studied. Firstly, the concepts of basic fuzzy event, fuzzy event and basic fuzzy event space are defined, related properties are investigated, and some results that will be [...] Read more.

In this paper, the problems of basic fuzzy event space and of probability fuzzy space are studied. Firstly, the concepts of basic fuzzy event, fuzzy event and basic fuzzy event space are defined, related properties are investigated, and some results that will be used in the next study of probability fuzzy space are obtained. Then, the definitions of the probability function for fuzzy events and probability fuzzy space are given, some properties of the defined probability function are obtained. In addition, some models of probability distribution of probability fuzzy space based on a known probability space are proposed, and some examples are given to show the usability of the proposed models of probability distribution. Full article

18 pages, 1146 KiB

Open AccessFeature PaperArticle

A Note on Estimation of Multi-Sigmoidal Gompertz Functions with Random Noise

by Patricia Román-Román, Juan José Serrano-Pérez and Francisco Torres-Ruiz

Mathematics 2019, 7(6), 541; https://doi.org/10.3390/math7060541 - 13 Jun 2019

Cited by 15 | Viewed by 4262

Abstract

The behaviour of many dynamic real phenomena shows different phases, with each one following a sigmoidal type pattern. This requires studying sigmoidal curves with more than one inflection point. In this work, a diffusion process is introduced whose mean function is a curve [...] Read more.

The behaviour of many dynamic real phenomena shows different phases, with each one following a sigmoidal type pattern. This requires studying sigmoidal curves with more than one inflection point. In this work, a diffusion process is introduced whose mean function is a curve of this type, concretely a transformation of the well-known Gompertz model after introducing in its expression a polynomial term. The maximum likelihood estimation of the parameters of the model is studied, and various criteria are provided for the selection of the degree of the polynomial when real situations are addressed. Finally, some simulated examples are presented. Full article

(This article belongs to the Special Issue Diffusion Processes Associated with Growth Curves: Probabilistic and Inferential Analysis)

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14 pages, 293 KiB

Open AccessArticle

On the Semilocal Convergence of the Multi–Point Variant of Jarratt Method: Unbounded Third Derivative Case

by Zhang Yong, Neha Gupta, J. P. Jaiswal and Kalyanasundaram Madhu

Mathematics 2019, 7(6), 540; https://doi.org/10.3390/math7060540 - 13 Jun 2019

Cited by 2 | Viewed by 2623

Abstract

In this paper, we study the semilocal convergence of the multi-point variant of Jarratt method under two different mild situations. The first one is the assumption that just a second-order Fréchet derivative is bounded instead of third-order. In addition, in the next one, [...] Read more.

In this paper, we study the semilocal convergence of the multi-point variant of Jarratt method under two different mild situations. The first one is the assumption that just a second-order Fréchet derivative is bounded instead of third-order. In addition, in the next one, the bound of the norm of the third order Fréchet derivative is assumed at initial iterate rather than supposing it on the domain of the nonlinear operator and it also satisfies the local

ω

-continuity condition in order to prove the convergence, existence-uniqueness followed by a priori error bound. During the study, it is noted that some norms and functions have to recalculate and its significance can be also seen in the numerical section. Full article

(This article belongs to the Special Issue Iterative Methods for Solving Nonlinear Equations and Systems)

11 pages, 259 KiB

Open AccessArticle

Three Results on the Nonlinear Differential Equations and Differential-Difference Equations

by Jianxun Rong and Junfeng Xu

Mathematics 2019, 7(6), 539; https://doi.org/10.3390/math7060539 - 13 Jun 2019

Cited by 16 | Viewed by 2857

Abstract

We mainly study the transcendental entire solutions of the differential equation

f^{n} (z) + P (f) = p_{1} e^{α_{1} z} + p_{2} e^{α_{2} z}

, where

p_{1}

,

p_{2}

, [...] Read more.

We mainly study the transcendental entire solutions of the differential equation

f^{n} (z) + P (f) = p_{1} e^{α_{1} z} + p_{2} e^{α_{2} z}

, where

p_{1}

,

p_{2}

,

α_{1}

and

α_{2}

are nonzero constants satisfying

α_{1} \neq α_{2}

and

P (f)

is a differential polynomial in f of degree

n - 1

. We improve Chen and Gao’s results and partially answer a question proposed by Li (J. Math. Anal. Appl. 375 (2011), pp. 310–319). Full article

(This article belongs to the Section Mathematics and Computer Science)

7 pages, 221 KiB

Open AccessArticle

On Bilateral Contractions

by Chi-Ming Chen, Gholamreza Heidary Joonaghany, Erdal Karapınar and Farshid Khojasteh

Mathematics 2019, 7(6), 538; https://doi.org/10.3390/math7060538 - 12 Jun 2019

Cited by 7 | Viewed by 2670

Abstract

In this manuscript, we introduce a new type of contraction, bilateral contraction which merges two significant approaches in the fixed point theory: Caristi type contractions and Jaggi type contractions. The principal aim of the main result is to enrich the literature by combining [...] Read more.

In this manuscript, we introduce a new type of contraction, bilateral contraction which merges two significant approaches in the fixed point theory: Caristi type contractions and Jaggi type contractions. The principal aim of the main result is to enrich the literature by combining the techniques of the mentioned two celebrated results that belong to Jaggi and Caristi. We consider an example to indicate the validity and genuine nature of the main result. Full article

(This article belongs to the Special Issue Recent Advances in Fixed Point and Best Proximity Point Problems and Their Applications)

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Mathematics, Volume 7, Issue 6 (June 2019) – 83 articles

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