Elementary Petri Net

Directed bipartite graph with

• Places (circles or ovals)
  • Represent some type of resource
• Transitions (rectangles or lines)
  • Consume and produce resources
• Arcs (places to transitions, transitions to places)
• Tokens, placed in places
• Initial marking, tokens in places

eg:

Modifications to it include:
PT Petri Net
Coloured Petri Net