Reality is a set of points in Euclidean n-space Rn, represented by ordered n-tuples of real numbers. A pair of points A and B represent the located vector or directed line segment called AB. The Euclidean n-space Rn in which the operations of vector addition, scalar multiplication and inner product act on have distances and angles between line segments or vectors which satisfy certain conditions which makes it a Euclidean space. One of those conditions is that it must satisfy the following linear equation. The inner product of any two real n-vectors x and y is defined by Please Register or Log in to view the hidden image! The distance or length of a vector is real and defined by the equation Please Register or Log in to view the hidden image!, hence is always non-negative. A real coordinate space together with Euclidean structure is called a Euclidean space and it defines reality.