Exercise: What is the relationship between DAGs and posets?

A **directed graph** is a pair (Nodes,Edges), where Nodes is a set, and Edges is a binary relation on Nodes, i.e., Edges is a set of ordered pairs of nodes. The graph is **acyclic** if there is no non-empty path of edges that leads from a node back to itself. A **DAG** is a directed graph that is acyclic.