“…According to Wang, 9 by means of Θ p we can take an invertible transformation in which { y 1 , … , y p } and { ϵ 1 , … , ϵ p } are bi‐orthonormal: where I p is an identity matrix of order p . Under this transformation (called the generalized synchronization transformation), the state variable U of system () turns into where in which W is called the null controllable part, while V is called the synchronizable state part.…”