# isCyclic(Digraph) -- determines whether a digraph is cyclic

## Synopsis

• Function: isCyclic
• Usage:
C = isCyclic D
• Inputs:
• D, an instance of the type Digraph,
• Outputs:
• C, , Whether the digraph D is cyclic

## Description

A digraph is cyclic if it contains a cycle, i.e. for some vertex v of D, by following the edges of D, one can return to v.

 i1 : D = digraph ({{0,1},{0,2},{2,3},{3,4},{4,2}},EntryMode=>"edges") o1 = Digraph{0 => {1, 2}} 1 => {} 2 => {3} 3 => {4} 4 => {2} o1 : Digraph i2 : isCyclic D o2 = true