Place
Also known as: Petri net place
A place in a Petri net is a node that holds tokens. Places represent local conditions, buffers, or resource pools; transitions are the events that move tokens between them.
The number of tokens in each place is the marking. A place with capacity 1 and a single token is the usual drawing of a mutex: enter consumes it, exit returns it.
Edges never connect place-to-place or transition-to-transition. The bipartite rule keeps “where tokens sit” separate from “what can fire.”