 A graph is formed by a collection of vertices and edges , where the vertices are structureless objects that are connected in pairs by edges . In the case of a directed graph , each edge has an orientation , from one vertex to another vertex . A path in a directed graph can be described by a sequence of edges having the property that the ending vertex of each edge in the sequence is the same as the starting vertex of the next edge in the sequence ; a path forms a cycle if the starting vertex of its first edge equals the ending vertex of its last edge . A directed acyclic graph is a directed graph that has no cycles . 
 A graph is formed by a collection of vertices and edges , where the vertices <a href='drop_aux' title='1'><mark>are</mark></a>structureless objects <a href='null_relcl' title='2'><mark>that</mark></a>are connected in pairs by edges . In the case of a directed graph , each edge <a href='got' title='3'><mark>has</mark></a> an orientation , from one vertex to another vertex . A path in a directed graph can be described by a sequence of edges having the property that the ending vertex of each edge in the sequence is the same as the starting vertex of the next edge in the sequence ; a path <a href='uninflect' title='4'><mark>forms</mark></a> a cycle if the starting vertex of its first edge <a href='uninflect' title='5'><mark>equals</mark></a> the ending vertex of its last edge . A directed acyclic graph <a href='drop_aux' title='6'><mark>is</mark></a>a directed graph <a href='null_relcl' title='7'><mark>that</mark></a><a href='got' title='8'><mark>has</mark></a> no cycles . 
A graph is formed by a collection of vertices and edges , where the vertices structureless objects r connected in pairs by edges . In the case of a directed graph , each edge got an orientation , from one vertex to anotha vertex . A path in a directed graph can be described by a sequence of edges having the property dat the ending vertex of each edge in the sequence is the same as the starting vertex of the next edge in da sequence ; a path form a cycle if tdastarting vertex of its first edge equal thdanding vertex of its last edge . A directed acyclic graph a directed graph got no cycles .