Изменения

|definition=<tex>\mathbb{R}^n, \Pi = \langle a_1; b_1 \rangle \times \cdots \times \langle a_n; b_n \rangle = \{\bar x = (x_1; x_2 \ldots x_n), x_j \in \langle a_j; b_j \rangle\}</tex>