After moving to the next bond, the state is, similarly: | ψ ψ D ⟩ ⟩ = 1 − − ϵ ϵ n + 1 | ψ ψ ′ D ⟩ ⟩ + ϵ ϵ n + 1 | ψ ψ ′ D ⊥ ⊥ ⟩ ⟩ The error, after the second truncation, is: ϵ ϵ = 1 − − | ⟨ ⟨ ψ ψ | ψ ψ D ′ ⟩ ⟩ | 2 = 1 − − ( 1 − − ϵ ϵ n + 1 ) | ⟨ ⟨ ψ ψ | ψ ψ D ⟩ ⟩ | 2 = 1 − − ( 1 − − ϵ ϵ n + 1 ) ( 1 − − ϵ ϵ n ) and so on, as we move from bond to bond.