PTnet Definitions – Siphons and Traps
20/3/2014
CE-653 - PTnet Theory and some Algorithms
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}Theorem[Minimal Siphon for General PTnets]
}Let N = (S, T, F) be a net, D ≤ S a siphon of N and ND the subnet of N generated by D U •D.
}D is minimal iff there exists a circuit Γ in ND (not necessarily elementary) that passes through all places of D such that for every transition t in Γ either:
}|•t ∩ D| = 1 (if net is FC) or
}|•t ∩ D| ≥ 2 and the places of (•t ∩ D) belong to an
alternating circuit
D
p1
p2