Graph Glossary

This is a partial listing of graph-related terms.
 * Half-edge graph: a unary edge (i.e., an edge that "connects" one vertex). It has limited practical application and is primarily discussed in mathematics.
 * Multi-graph: There are many situations in which it is desirable to have multiple edges between the same two vertices.
 * Simple graph: the prototypical graph, where an edge connects two vertices and no loops are allowed
 * Weighted graph: used to represent strength of ties or transition probabilities
 * Vertex-labeled graph: Most every graph makes use of labeled vertices (e.g., an identifier).
 * Semantic graph: used to model cognitive structures such as the relationship between concepts and the instances of those concepts [2]
 * Vertex-attributed: used in applications where it is desirable to append non-relational metadata to a vertex
 * Edge-labeled graph: used to denote the way in which two vertices are related (e.g., friendships, kinships, etc.)
 * Directed graph: orders the vertices of an edge to denote edge orientation
 * Hypergraph: generalizes a binary edge whereby an edge connects an arbitrary number of vertices [3]
 * Undirected graph: the typical graph that is used when the relationship is symmetric (e.g., friendship)
 * Resource description framework graph: a graph standard developed by the World Wide Web consortium that denotes vertices and edges by uniform resource identifiers [4]
 * Edge-attributed graph: used in applications where it is desirable to append non-relational metadata to an edge
 * Pseudo graph: used to denote a reflexive relationship