had to be formulated with a postulation which can be shown to be equivalent to the method of path integral (see mathematical detail ). It was postulated that the momentum p and position q are no longer mere numbers but are operators satisfying the commutative relation: (qp - pq) = i . This is called the canonical quantization. The fact that the particle is endowed with wave property is referred to as first quantization. Actually only p is treated as an operator - a differential operator acting on the wave function (q), q remains to be a c-number. The commutative relation can be viewed as a mathematical statement for the Uncertainty Principle. Since it implies that p cannot be a function of q (because it would mean p and q can be determined precisely at the same time), p can be related to q only in the form of an operator such as - i d/dq, where i = . The commutative relation is the direct result of such interpretation. Application of this rule for p and q to the equation relating the total energy E to the kinetic energy p 2 /2m and the potential energy V(q), e.g., E = p 2 /2m + V(q), yields the time-independent Schrodinger Equation for one particle with mass m and interacting potential V (i.e., it describes the stationary states with well-defined energy E corresponding to E 0, and t in the uncertainty relation t E &gt; ) : For a given interacting