Description: A directed subgraph is a fundamental concept in graph theory, referring to a subgraph formed from a subset of the vertices and edges of a directed graph. In this context, a directed graph consists of a set of vertices (or nodes) and a set of edges (or arcs) that have a specific direction, meaning each edge connects a source vertex to a target vertex. A directed subgraph maintains this directional property, which means that if an edge belongs to the subgraph, its direction must be the same as in the original graph. This characteristic allows for the study of local properties of a larger graph, facilitating the analysis of complex structures. Directed subgraphs are useful for representing specific relationships within a broader system, such as information flows, communication networks, or organizational hierarchies. Additionally, they can be used to simplify computational problems, allowing researchers and developers to focus on relevant parts of the graph without losing the directional structure that is crucial for analysis. In summary, directed subgraphs are essential tools in graph theory, providing a framework for understanding and manipulating complex relationships in various applications.