How can deadlocks be represented?

Deadlocks are able to be described in terms of a directed graph called as a system resource-allocation graph. This graph contains of the following:

• a set of vertices V
• a set of edges E
• The set of vertices V is partitioned in to dissimilar types of nodes = {p₁, p2...} the set of active process in the system, and R= {r₁, r2...} the set of resource in the system.

P_i      R_j indicates that process pi has requested an instance of resource type Rj and is waiting currently for the resource. This is called as the request edge.

 R_j      Pi indicates that an instance of resource Rj has been allocated to process Pi. This is called as the assignment edge.