High Quality Content by WIKIPEDIA articles! In mathematics, a ball is the inside of a sphere. It may be either a closed ball (including the boundary points) or an open ball (excluding them). These concepts are defined not only in three-dimensional Euclidean space but also for lower and higher dimensions, and for metric spaces in general. A ball in the Euclidean plane, for example, is the same thing as a disk, the area bounded by a circle. In mathematics contexts where the term "ball" is used, the word "sphere" is usually assumed to refer to the boundary points only (namely, a spherical surface in three-dimensional space). In other contexts, such as in Euclidean geometry and informal use, "sphere" may be sometimes mean "ball".

Данное издание не является оригинальным. Книга печатается по технологии принт-он-деманд после получения заказа.