space), it can be written as: where e 1 = (1,0,0...,0), e 2 = (0,1,0...,0), e 3 = (0,0,1...,0),..., e n = (0,0,0...,1) is the standard basis set of vectors for the space R n , and i = 1, 2,... n is an index labelling components. Each vector has exactly