ANALYSIS AND IMPLEMENTATION OF LIVENESS OF S-COMPOSITION PETRI NET

Let ∑1 = (N1,M1),∑2 = (N2,M2) be two Petri nets, and do not contain freezing tokens. Ni = (Si,Ti;Fi), i = 1, 2,, T1 ∩ T2 = Φ, S1 ∩ S2 ≠Φ, s-composition Petri net ∑s is defined on Petri nets ∑1 and ∑2 in this paper. The liveness of ∑s is discussed, and if ∑1 and ∑2 are live, some deciding conditions for preserving liveness of ∑s is given based on the concept of the mutually inverse ordered pair places of Scomposition Petri net. For two live and bounded Petri nets, if any two merging places are not a mutually inverse ordered pair places, then their S-composition Petri net is live and bounded. If ∑s, is not live, a control device for irnplementing liveness is presented.