| Scientists and engineers work with real and complex numbers. In a quantity of cases, they utilize topological properties of these numbers. To find derivatives and integrals, we need existence of limits. In their turn, limits are topological constructions. It means that manipulations with limits and, consequently, with derivatives and integrals are based on the topology of number spaces. Number spaces, the real and complex lines, as well as Euclidean spaces have a good topology that allows mathematicians to develop calculus and optimization methods in these spaces. They are metric spaces, which possess a lot of useful features. These features provide for solution of many theoretical and practical problems. |