Definition: The term "adjacency" is a type of relationship between two or more items, typically in a matrix or network structure. In computer science and mathematics, it refers to the relation between nodes (such as vertices) in a graph. In general, adjacency can be thought of as a way to represent relationships between objects or events. For example, if we have a directed graph where edges point from one vertex to another, then the relationship between two vertices is that they are adjacent in this graph. The term "adjacency" also has a technical meaning in computer science and mathematics, which refers to the relation between two variables or values, such as nodes or edges, within a data structure. In other words, an adjacency matrix in a graph is like a square table where each entry represents a directed edge from one vertex to another. Here are some examples of how adjacency can be defined: - A graph with n vertices and m edges is called a complete graph, where all edges point towards the same node. - An undirected graph has no cycles and is known as an unweighted graph. In this case, nodes represent points in space (as in 3D geometry or 2D coordinate systems), edges are lines connecting them, and there are no weights assigned to these lines. The definition of adjacency can be more specific depending on the context, such as whether we consider only direct connections between vertices or all possible paths. For example, a graph that has cycles is not considered to have adjacency unless it also satisfies certain other properties (such as being connected).

adjacency