Theorem (Gram-Schmidt Orthonormalization Process) Given a linearly independent subset {a, ... ,a} of , the set of vectors {v, ... ,v} defined below is an ONB of span().
Let span{a, ... ,a}, and define recursively by
Thus each v results from normalizing the component of a perpendicular to . As a result, {v, ... ,v} is an ONB for , for each 1 .