Basics of petri nets Petri net consist two types of nodes: places and transitions. And arc exists only from a place to a transition or from a transition to a place a place may have zero or more tokens Graphically, places, transitions, arcs, and tokens are represented respectively by: circles, bars, arrows and dots Below is an example petri net with two places and one transaction 15Basics of Petri Nets ◼ Petri net consist two types of nodes: places and transitions. And arc exists only from a place to a transition or from a transition to a place. ◼ A place may have zero or more tokens. ◼ Graphically, places, transitions, arcs, and tokens are represented respectively by: circles, bars, arrows, and dots. ◼ Below is an example Petri net with two places and one transaction. p 15 p1 2 t1