Let v(w) ∈ R m be the wth row of O normalized to have unit 2-norm: A crucial aspect of this representational scheme is that its correctness is invariant to scaling and rotation.
clustering the normalized rows of diag(s)O a diag(s 2 )Q where O a is any element-wise power of O with any a = 0, Q ∈ R m×m is any orthogonal transformation, and s 1 ∈ R n and s 2 ∈ R m are any positive vectors yields the correct clusters under the model.