# 4.11. Glossary¶

**Complete Graph:** A complete graph is a graph where every node is connected to every other.

**Connected Graphs:** A graph is connected if there is a path from every node to every other node.

**Directed Edge:** This kind of edge is constrained to a single direction and is asymmetrical to each node it is connected to. Also comparable to a one way street.

**Directed Graph:** A directed graph is a graph, i.e., a set of objects (called vertices or nodes) that are connected together, where all the edges are directed from one vertex to another.

**ER Graphs:** The ER model is either of two closely related models for generating random graphs. The ER graph G(n, p) contains n nodes, and each pair of nodes is connected by an edge with probability p.

**Edges:** An edge of a network is one of the connections between the nodes (or vertices) of the network.

**Graph Theory:** Graph theory is the study of graphs, a mathematical structure used to model pairwise relations between objects from a certain collection. A graph in this context refers to a collection of vertices or nodes and a collection of ed.

**Graph Algorithm:** A graph algorithm is an algorithm that takes one or more graphs as inputs.

**Graph:** A graph is a representation of a system that contains discrete, interconnected elements.

**NetworkX:** NetworkX is a Python package for the creation, manipulation, and study of the structure, dynamics, and functions of complex networks.

**Nodes** *(vertices)* **:** A node represents the information contained in a single data structure. These nodes may contain a value or condition, or possibly serve as another independent data structure.

**Path:** A path is a sequence of nodes with an edge between each consecutive pair.

**Random Graph:** A graph with nodes and edges generated at random.

**Stack:** A stack is an Abstract Data Type (ADT) in which elements are added or removed from the top of the stack, in a “last in first, first out” or LIFO order.

**Undirected Edge:** This kind of edge is not constrained to a single direction and is symmetrical to each node it is connected to. Also is comparable to a two way street.

**Undirected Graph:** An undirected graph is a graph, i.e., a set of objects (called vertices or nodes) that are connected together, where all the edges are bidirectional.