Equation Icon  d --v(t)∗H (k )v (t) = [P (ik)v(t)]∗H (k )v(t) + v(t)∗H (k)P(ik)v(t) dt ∗ ∗ = v(t) [P (ik) H (k) + H (k)P (ik )]v(t) ≤ 2αv (t)∗H (k )v (t),