For a dimensionless constant π π = L a 1 T a 2 V a 3 , we are looking for vectors a = [ a 1 , a 2 , a 3 ] such that the matrix-vector product M a equals the zero vector [ 0 , 0 ] . In linear algebra, the set of vectors with this property is known as the kernel (or nullspace) of the dimensional matrix. In this particular case its kernel is one-dimensional. The dimensional matrix as written above is in reduced row echelon form, so one can read off a non-zero kernel vector to within a multiplicative constant: a = [ − − 1 1 1 ] .