Consider a one-dimensional system with the Hamiltonian 1 H=1 (+ + Pq*) 2 The set of canonical transformation (P, Q) that reduces H to the form of a harmonic oscillator, is 1 Q = -, P = pq 9 1, p =-pq P 9 2 Q=, 9 P = pq 0=--, P=-pq 9