K-cell (mathematics)

Projections of K-cells onto the plane (from to ). Only the edges of the higher-dimensional cells are shown.

A -cell is a higher-dimensional version of a rectangle or rectangular solid. It is the Cartesian product of closed intervals on the real line.[1] This means that a -dimensional rectangular solid has each of its edges equal to one of the closed intervals used in the definition. The intervals need not be identical. For example, a 2-cell is a rectangle in such that the sides of the rectangles are parallel to the coordinate axes. Every -cell is compact.[2][3]