Abundant semigroups with a quasi-ideal quasi-adequate transversal

Characterization theorems for abundant sernigroups having a quasi-ideal quasi-adequate transversal are obtained. Our results generalize and amplify the related results of Satio on regular semigroup obtained in 1985 and Kong obtained in 2007 respectively. Some recent results on this topic given by Guo-Shum are strengthened. In particular, the structure of such an abundant semigroup is described.     

Global asymptotic stability of an almost periodic nonlinear ecological model

An almost periodic nonlinear predator–prey system with N prey species and M predator species is revisited in this paper. A set of essentially new criteria are obtained for the existence and global asymptotic stability of a unique positive almost periodic solution. The obtained results provide an answer to an open problem arising in a recent paper. Not only an important restriction of their theorem is removed, but also some other conditions are weakened in this paper. Moreover, a mistake in their assumption is corrected. By applying the obtained results to some special predator–prey systems and competitive systems, many earlier results are significantly improved. Finally, several illustrative examples and their simulations are provided to show the effectiveness of the obtained results.     

Cavity flow simulation of Carreau–Yasuda non-Newtonian fluids using PIM meshfree method

Lid-driven cavity flow of a purely-viscous non-Newtonian fluid obeying Carreau–Yasuda rheological model is studied numerically using the PIM meshfree method combined with the Characteristic-Based Split-A algorithm. Results are reported for the velocity and pressure profiles at Reynolds numbers as high as 1000 for a non-Newtonian fluid obeying Carreau–Yasuda rheological model. For Newtonian fluids, results obtained from our PIM–CBS-A method show good agreement with benchmark results published in the literature and obtained using finite difference and/or Finite Element Methods. Our numerical results are also consistent with recent published results obtained using another meshfree method called LSM with the advantage that PIM needs less “points” to achieve the same degree of accuracy. Results obtained for the Carreau–Yasuda model reveals the strong effect of the shear-thinning behavior of a fluid on its flow kinematics within the cavity.     

Propagation of Rayleigh waves in generalized magneto-thermoelastic orthotropic material under initial stress and gravity field

In this paper the influence of the gravity field, relaxation times and initial stress on propagation of Rayleigh waves in an orthotropic magneto-thermoelastic solid medium has been investigated. The solution of the more general equations are obtained for thermoelastic coupling by Helmoltz’s theorem. The frequency equation which determines Rayleigh wave velocity have been obtained. Many special cases are investigated from the present problem. Numerical results analyzing the frequency equation are obtained and presented graphically. Relevant results of previous investigations are deduced as special cases from these results. The results indicate that the effect of initial stress, magnetic field and gravity field are very pronounced.     

Global attractivity for nonlinear fractional differential equations

We present some results for the global attractivity of solutions for fractional differential equations involving Riemann-Liouville fractional calculus. The results are obtained by employing Krasnoselskii’s fixed point theorem. Similar results for fractional differential equations involving Caputo fractional derivative are also obtained by using the classical Schauder’s fixed point theorem. Several examples are given to illustrate our main results.     

M1-空间的和定理

In this gaper, two sum theorems for M₁-spaces are obtained. These results improve two results obtained by Gao Guoshi in [ 2 ] respectively. A result for M₀-spaces is also obtained which answers J.Nagata's question partly.     

On tightness and stopping times

This paper studies conditions of tightness for sequences of processes, which conditions are mostly based on the use of ‘dominating’ increasing processes. The results obtained follow in directions initiated by Aldous and Rebolledo and are particularly well-suited for studying sequences of semimartingales. Also obtained are results that extend sufficient conditions of Aldous's type to processes that are not quasi-left-continuous.     

Generalized Vector Variational Inequalities

In this paper, we introduce a generalized vector variational inequality problem (GVVIP) which extends and unifies vector variational inequalities as well as classical variational inequalities in the literature. The concepts of generalized C-pseudomonotone and generalized hemicontinuous operators are introduced. Some existence results for GVVIP are obtained with the assumptions of generalized C-pseudomonotonicity and generalized hemicontinuity. These results appear to be new and interesting. New existence results of the classical variational inequality are also obtained.     

Fourth-Order p-Laplacian Nonlinear Systems via the Vector Version of Krasnosel’skiĭ’s Fixed Point Theorem

In this paper, existence results for a fourth-order nonlinear system are obtained. Both classical and vector versions of the Krasnosel’skiĭ’s fixed point theorem are used and a comparison of the obtained results to those from the literature is provided.     

A queue with a pair of instantaneous independent bernoulli feedback processes

In this paper we are concerned with several random processes that occur in M/G₂/l queue with instantaneous feedback in which the feedback decision process is a pair of independent Bernoulli processes. The stationary distribution of the output process has been obtained. Results for particular queues with feedback and without feedback are obtained. Some operating characteristics are derived for this queue. Some interesting results are obtained for departure processes. Optimum service rate is obtained. Numerical examples are provided to test the feasibility of the queueing model     

Further results on the Aanderaa-Rosenberg conjecture

Some results on the “evasiveness” of graph properties are obtained, extending the work of Rivest and Vuillemin. In particular, it is shown that any nontrivial monotone graph property on n vertices is at least $\text{n}{}^2\text{9}\text{-}\text{evasive}$; particular stronger results are obtained for values of n that are powers of primes less than 14. A new result allowing interpolation among n values is obtained, as are some stronger results on restricted classes of properties.     

On the curvature of contact metric manifolds

Some results on Ricci-symmetric contact metric manifolds are obtained. Second order parallel tensors and vector fields keeping curvature tensor invariant are characterized on a class of contact manifolds. Conformally flat contact manifolds are studied assuming certain curvature conditions. Finally some results onk-nullity distribution of contact manifolds are obtained.     

Komlos-Major-Tusnady approximation for the general empirical process and Haar expansions of classes of functions

Rates of convergence of the Komlos-Major-Tusnady type in the invariance principle for empirical processes indexed by functions are obtained. The conditions are given in terms of the empirical entropy and the accuracy of the Haar type approximation for the corresponding classes of functions. The recent results of Massart⁽²⁵⁾ as well as some new results for empirical characteristic functions are obtained as a corollary.     

Quadrilateral embeddings of bipartite graphs

Current graphs and a theorem of White are used to show the existence of almost complete regular bipartite graphs with quadrilateral embeddings conjectured by Pisanski. Decompositions of K_n and K_{n, n} into graphs with quadrilateral embeddings are discussed, and some thickness results are obtained. Some new genus results are also obtained.     

Solvability of a class of impulsive damped vibration problems

In this paper, a class of impulsive damped vibration problems are considered. Existence results are obtained by using variational method and critical point theorem. The obtained results are also valid and new even if the impulsive damped vibration problem is reduced to impulsive Hamiltonian system and Hamiltonian system. Examples are presented to illustrate the feasibility and effectiveness of the results. Copyright © 2013 John Wiley & Sons, Ltd.     

Homoclinic Orbits for Second Order Discrete Hamiltonian Systems with Potential Changing Sign

In this paper, a class of second order discrete Hamiltonian systems without any periodicity assumptions are considered. Base on the critical point theory, some sufficient conditions for the existence of homoclinic orbits are obtained. The results obtained extend the results in [2006] by relaxing the assumptions on the sign of the potential.      

On semidirect products and wreath products of partially ordered groups

The notions of Cartesian and semidirect products for partially ordered groups are considered. A series of results on those products of AO \mathcal{A}\mathcal{O} -groups and interpolation groups is obtained. Some results concerning wreath products of directed groups are obtained.     

The quadratic plus the tensor potentials for particle with 1/2‐spin via L2 method under the spin symmetry

In the present letter, the relativistic equation for particle 1/2‐spin have been obtained for the quadratic scalar and vector potentials in the presence of the tensor interaction that depends on the radial component either linearly and inversely. Under the spin symmetry, the relativistic equation is calculated by using the idea of L² that supports a tridiagonal matrix representation of the wave operator. By this requirement, the relativistic energy spectrum and corresponding spinor wave functions are obtained. Also, the obtained analytically result is compared with other results that are in good agreement. Some of the numerical results are given, too. Copyright © 2015 John Wiley & Sons, Ltd.     

Some nondifferentiable multiobjective programming under generalized d-V-type-I univexity

In this paper, we introduce new classes of functions called d-V-type-I univex by extending the definition of d-V-type-I functions and consider a multiobjective optimization problem involving generalized d-V-type-I univex functions. A number of Karush–Kuhn–Tucker-type sufficient optimality conditions are obtained for a feasible solution to be a weak Pareto efficient solution. The Mond–Weir-type duality results are also presented. The results obtained in this paper generalize and extend the previously known result in this area.     

On the E-Epigraph of an E-Convex Function

In Ref 1, Yang shows that some of the results obtained in Ref. 2 on E-convex programming are incorrect, but does not prove that the results which make the connection between an E-convex function and its E-epigraph are incorrect. In this note, we show that the results obtained in Ref. 2 concerning the characterization of an E-convex function f in terms of its E-epigraph are incorrect. Afterward, some characterizations of E-convex functions using a different notion of epigraph are given.