Comment on the article “On the existence of the N-body Efimov effect” by X.P. Wang

It is shown that the proof of the main theorem in the article “On the existence of the N-body Efimov effect” by X.P. Wang [J. Funct. Anal. 209 (2004) 137–161], is incorrect.     

A note on the paper “Resource-constrained project scheduling: Notation,classification, models and methods” by Brucker et al.

The great variety of project scheduling problems studied in the ever growing literature motivated the recent development of classification schemes. In a recent paper (European Journal of Operational Research 112 (1999) 3–41), Brucker et al. make the claim that, so far, no classification scheme exists which is compatible with what is commonly accepted in machine scheduling and introduce a new classification. In this note, we critically review major shortcomings of the suggested scheme which place heavy limitations on its potential use.     

A commentary “on the periodic solutions of a forced second-order equation” by S. P. Hastings and J. B. McLeod

Summary We discuss the relationship of the shooting and perturbation methods used by Hastings and McLeod in the paper On the Periodic Solutions of a Forced Second-Order Equation to the geometrical techniques of nonlinear dynamical systems theory.     

Comments on the paper by A. V. Borisov,A. A. Kilin,I. S. Mamaev “How to control the Chaplygin ball using rotors. II”

In this paper we consider the control of a dynamically asymmetric balanced ball on a plane in the case of slipping at the contact point. Necessary conditions under which a control is possible are obtained. Specific algorithms of control along a given trajectory are constructed.     

A comment on “Global solutions for nonlinear fuzzy fractional integral and integrodifferential equations”

In a recent paper Alikhani and Bahrami (in press) [1], we found some defects about the exact solutions of given examples. Also, the main result (Theorem 4.5) is not fulfilled. For this purpose, some examples are given.     

Comment on paper “Multi-strategy ensemble evolutionary algorithm for dynamic multi-objective optimization” by Wang and Li

This comment addresses the work of Wang and Li (DOI: 10.1007/s12293-009-0012-0, hereafter referred to as WL) published online on September 01, 2009 in a (special) issue of Memetic Computing. We respectfully beg to differ in opinion with WL and argue that the concept of multi-strategy evolutionary search used by WL is not particularly novel. Similar ideas have been presented elsewhere, and these publications date back to at least early 2007. For instance, in a series of papers published in PNAS (2007), SSSAJ (2008), WRR (2008), IEEE-TEVC (2009), JH (2010), Vrugt and coworkers have introduced AMALGAM, a multi-method (or ensemble) search approach to solve emerging single and multiple objective search and optimization problems. In the past few years, MATLAB, C++, Python, and R implementations of AMALGAM have been distributed extensively among researchers and practitioners in various fields of study.     

A new class of polynomial primal–dual methods for linear and semidefinite optimization

We propose a new class of primal–dual methods for linear optimization (LO). By using some new analysis tools, we prove that the large-update method for LO based on the new search direction has a polynomial complexity of O(n^4/(4+ρ)log(n/ε)) iterations, where ρ∈[0,2] is a parameter used in the system defining the search direction. If ρ=0, our results reproduce the well-known complexity of the standard primal–dual Newton method for LO. At each iteration, our algorithm needs only to solve a linear equation system. An extension of the algorithms to semidefinite optimization is also presented.     

A Comment the BooK“continuous-Time Markov Chains” by W.J.Anderson

The book "Continuous-Time Markov Chains" by W. J. Anderson collects a large part of the development in the past thirty years. It is now a popular reference for the researchers on this subject or related fields. Unfortunately, due to a misunderstanding of the approximating methods, several results in the book are incorrectly stated or proved. Since the results are related to the present author's work, to whom it may be a duty to correct the mistakes in order to avoid further confusion. We emphasize the approximating methods because they are useful in many situations.     

A Note on a Problem of M. S. Berger

In this paper, we discuss the problem concerning global and local structure of solutions of an operator equation posed by M. S. Berger. Let f : U (?)E→ F be a C1 map, where E and F are Banach spaces and U is open in E. We show that the solution set of the equation f(x)=y for a fixed generalized regular value y of f is represented as a union of disjoint connected C1 Banach submanifolds of U, each of which has a dimension and its tangent space is given. In particular, a characterization of the isolated solutions of the equation f(x) = y is obtained.     

“Small sample properties of ML,COLS and DEA estimators of frontier models in the presence of heteroscedasticity” by A.N. Bojanic,S.B. Caudill and J.M. Ford,European Journal of Operational Research 108, 1998, 140–148: A comment

This paper comments on the paper by Bojanic et al. (1998) in this Journal.