“…Theorem (Sheng and Zhu) Let V ( t , x ) be twice differentiable on . Then we have where V t ( t , x ) is the partial derivatives of the function V ( t , x ) in t, ∇ x V ( t , x ) is the gradient of V ( t , x ) in x and ‖·‖ 1 is the 1‐norm for vectors, ie, for p =( p 1 , p 2 ,⋯, p n ) τ .…”