α 1 = X ( τ 1 ) y ∥ X ( τ 1 ) ∥ … α j + 1 = X ( α j + 1 ) y ∥ X ( τ j + 1 ) ∥ , α j + 2 = X ( τ j + 2 ) y ∥ X ( τ j + 2 ) ∥ \alpha_{1}=\frac{X(\tau_{1})y}{\parallel X(\tau_{1})\parallel} \dots \alpha_{j+1} = \frac{X(\alpha_{j+1})y}{\parallel X(\tau_{j+1})\parallel},\alpha_{j+2}=\frac{X(\tau_{j+2})y}{\parallel X(\tau_{j+2})\parallel}