On ‘valid sequences’ considered by Wigner

On an arithmetic function considered by Pillai

For every positive integer n let p(n) be the largest prime number p ≤ n. Given a positive integer n = n1, we study the positive integer r = R(n) such that if we define recursively ni+1 = ni − p(ni) for i ≥ 1, then nr is a prime or 1. We obtain upper bounds for R(n) as well as an estimate for the set of n whose R(n) takes on a fixed value k.

Choosing a Medical Specialty: Factors Considered by Iranian General Practitioners

Background: For medical students, the selection of a specialty is one of the most critical decisions to be made. On a personal level, it determines lifetime career achievements and, for the community, it directly affects the outcome of public health programs. The aim of this study was to investigate which factors were more important among Iranian residents when considering a specialty. Methods:...

Faculty Members’ Evaluation by Students: Valid or Invalid

Introduction: Evaluation of university faculty members which is aimed to improve teaching quality is performed through several methods. One of the most common and conflicting methods is faculty evaluation by students. This method is commonly used in most universities in spite of controversy over its validity. This paper presents a glance at the current research literature on the viewpoints of f...

Detection of 3-nitrotyrosine in proteins and tissues is considered a valid marker of oxidative stress

Minimal Valid Automata of Sample Sequences for Discrete Event Systems

Minimal valid automata (MVA) refer to valid automata models that fit a given input-output sequence sample from a Mealy machine model. They are minimal in the sense that the number of states in these automata is minimal. Critical to system identification problems of discrete event systems, MVA can be considered as a special case of the minimization problem for incompletely specified sequential m...