Description: A DAG, or directed acyclic graph, is a fundamental data structure in graph theory characterized by being a directed graph that contains no cycles. This means that by following the edges of the graph, it is not possible to return to a previously visited node. DAGs are used in various applications due to their ability to represent hierarchical relationships and dependencies. Each node in a DAG can represent an object, task, or event, while the edges indicate the direction of the relationship or dependency between them. This structure allows for a clear and efficient representation of processes where the order of execution is crucial, such as in task scheduling or dependency resolution in software projects. Additionally, DAGs are essential in search and optimization algorithms, as they facilitate the identification of paths and the resolution of complex problems. Their acyclic nature ensures that there is no ambiguity in relationships, making them a valuable tool in the design of systems and communication protocols, as well as in the implementation of version control systems, where precise tracking of changes and their history is required. In summary, DAGs are a powerful and versatile representation that allows modeling and solving problems across multiple domains of computer science and graph theory.