Abstract
The paper deals with the deduction of the condition logic equations representing the relations between conditions in the condition/event (C/N) system from the S-invariant and the related token count equation defined in the ordinary Petri net.
The aim is to construct the powerful analytical tool for solving the problem how to find the equivalent C/E system with the less number of conditions than of conditions in an original C/E system.
This problem will be occured, e.g., in the logic circuit design from the specification of the discrete event control system represented by the C/E system.
At first, the concept of the minimum support nets (MSNs) in the ordinary Petri net are introduced corresponding to the basic S-invariants. This concept is applied to C/E systems by using the complement of condition, and the generalized MSN (including the quasi MSN) are introduced. The condition logic equations are deduced from the token count equations related to the generalized MSN by adopting the modulo 2 addition. The simple application of the equations to eliminate conditions in the C/E system and to obtain the equivalent C/E system are shown by an example.
