The proof, known to be so hard that a mathematician once offered 10 martinis to whoever could figure it out, uses number ...

Abstract: Many real-world problems in different industrial and economic fields are permutation combinatorial optimization problems. Solving to optimality large instances of these problems, such as ...

Something tells you that you have outgrown it somehow, without any resentment, against anyone. Maybe there will be a shift in your heart today, and you might notice that a person, a habit, or even a ...

Spain’s Social Security website helps users access their personal data and services online. Credit : Ure, Shutterstock Misplaced your Spanish Social Security number and now a form is glaring at you in ...